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Ditton DM, Marchus CR, Bozeman AL, Martes AC, Brumley MR, Schiele NR. Visualization of rat tendon in three dimensions using micro-Computed Tomography. MethodsX 2024; 12:102565. [PMID: 38292310 PMCID: PMC10825692 DOI: 10.1016/j.mex.2024.102565] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2023] [Accepted: 01/09/2024] [Indexed: 02/01/2024] Open
Abstract
Micro-computed tomography (CT) is an X-ray-based imaging modality that produces three-dimensional (3D), high-resolution images of whole-mount tissues, but is typically limited to dense tissues, such as bone. The X-rays readily pass-through tendons, rendering them transparent. Contrast-enhancing chemical stains have been explored, but their use to improve contrast in different tendon types and across developmental stages for micro-CT imaging has not been systematically evaluated. Therefore, we investigated how phosphotungstic acid (PTA) staining and tissue hydration impacts tendon contrast for micro-CT imaging. We showed that PTA staining increased X-ray absorption of tendon to enhance tissue contrast and obtain 3D micro-CT images of immature (postnatal day 21) and sexually mature (postnatal day 50) rat tendons within the tail and hindlimb. Further, we demonstrated that tissue hydration state following PTA staining significantly impacts soft tissue contrast. Using this method, we also found that tail tendon fascicles appear to cross between fascicle bundles. Ultimately, contrast-enhanced 3D micro-CT imaging will lead to better understanding of tendon structure, and relationships between the bone and soft tissues.•Simple tissue fixation and staining technique enhances soft tissue contrast for tendon visualization using micro-CT.•3D tendon visualization in situ advances understanding of musculoskeletal tissue structure and organization.
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Affiliation(s)
- Destinee M. Ditton
- Chemical & Biological Engineering, University of Idaho, 875 Perimeter Dr. MS 0904, Moscow, ID 83844, USA
| | - Colin R. Marchus
- Chemical & Biological Engineering, University of Idaho, 875 Perimeter Dr. MS 0904, Moscow, ID 83844, USA
| | - Aimee L. Bozeman
- Psychology, Idaho State University, 921 S 8th Avenue Stop 8087, Pocatello, ID 83209, USA
| | - Alleyna C. Martes
- Psychology, Idaho State University, 921 S 8th Avenue Stop 8087, Pocatello, ID 83209, USA
| | - Michele R. Brumley
- Psychology, Idaho State University, 921 S 8th Avenue Stop 8087, Pocatello, ID 83209, USA
| | - Nathan R. Schiele
- Chemical & Biological Engineering, University of Idaho, 875 Perimeter Dr. MS 0904, Moscow, ID 83844, USA
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2
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Aguilar A, Gifre L, Ureña-Torres P, Carrillo-López N, Rodriguez-García M, Massó E, da Silva I, López-Báez V, Sánchez-Bayá M, Prior-Español Á, Urrutia M, Paul J, Bustos MC, Vila A, Garnica-León I, Navarro-González JF, Mateo L, Bover J. Pathophysiology of bone disease in chronic kidney disease: from basics to renal osteodystrophy and osteoporosis. Front Physiol 2023; 14:1177829. [PMID: 37342799 PMCID: PMC10277623 DOI: 10.3389/fphys.2023.1177829] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2023] [Accepted: 05/23/2023] [Indexed: 06/23/2023] Open
Abstract
Chronic kidney disease (CKD) is a highly prevalent disease that has become a public health problem. Progression of CKD is associated with serious complications, including the systemic CKD-mineral and bone disorder (CKD-MBD). Laboratory, bone and vascular abnormalities define this condition, and all have been independently related to cardiovascular disease and high mortality rates. The "old" cross-talk between kidney and bone (classically known as "renal osteodystrophies") has been recently expanded to the cardiovascular system, emphasizing the importance of the bone component of CKD-MBD. Moreover, a recently recognized higher susceptibility of patients with CKD to falls and bone fractures led to important paradigm changes in the new CKD-MBD guidelines. Evaluation of bone mineral density and the diagnosis of "osteoporosis" emerges in nephrology as a new possibility "if results will impact clinical decisions". Obviously, it is still reasonable to perform a bone biopsy if knowledge of the type of renal osteodystrophy will be clinically useful (low versus high turnover-bone disease). However, it is now considered that the inability to perform a bone biopsy may not justify withholding antiresorptive therapies to patients with high risk of fracture. This view adds to the effects of parathyroid hormone in CKD patients and the classical treatment of secondary hyperparathyroidism. The availability of new antiosteoporotic treatments bring the opportunity to come back to the basics, and the knowledge of new pathophysiological pathways [OPG/RANKL (LGR4); Wnt-ß-catenin pathway], also affected in CKD, offers great opportunities to further unravel the complex physiopathology of CKD-MBD and to improve outcomes.
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Affiliation(s)
- Armando Aguilar
- Autonomous University of Chiapas, Tuxtla Gutiérrez, Mexico
- Department of Nephrology, Mexican Social Security, IMSS General Hospital of Zone No 2, Tuxtla Gutiérrez, Mexico
| | - Laia Gifre
- Department of Rheumatology, Hospital Germans Trias i Pujol, Badalona (Barcelona), Catalonia, Spain
| | - Pablo Ureña-Torres
- AURA Saint Ouen, Department of Nephrology and Dialysis and Department of Renal Physiology, Necker Hospital, University of Paris Descartes, Paris, France
| | - Natalia Carrillo-López
- Bone and Mineral Research Unit, Instituto de Investigación Sanitaria del Principado de Asturias (ISPA), Oviedo, Asturias, Spain
| | - Minerva Rodriguez-García
- Nephrology Clinical Management Unit, Central University Hospital of Asturias (HUCA), Oviedo, Asturias, Spain
| | - Elisabeth Massó
- Department of Nephrology, University Hospital Germans Trias i Pujol (HGiTP), Badalona (Barcelona), Catalonia, Spain
- REMAR-IGTP Group, Research Institute Germans Trias i Pujol, Can Ruti Campus, Badalona (Barcelona), Catalonia, Spain
| | - Iara da Silva
- Department of Nephrology, University Hospital Germans Trias i Pujol (HGiTP), Badalona (Barcelona), Catalonia, Spain
- REMAR-IGTP Group, Research Institute Germans Trias i Pujol, Can Ruti Campus, Badalona (Barcelona), Catalonia, Spain
| | - Víctor López-Báez
- Department of Nephrology, University Hospital Germans Trias i Pujol (HGiTP), Badalona (Barcelona), Catalonia, Spain
- REMAR-IGTP Group, Research Institute Germans Trias i Pujol, Can Ruti Campus, Badalona (Barcelona), Catalonia, Spain
| | - Maya Sánchez-Bayá
- Department of Nephrology, University Hospital Germans Trias i Pujol (HGiTP), Badalona (Barcelona), Catalonia, Spain
- REMAR-IGTP Group, Research Institute Germans Trias i Pujol, Can Ruti Campus, Badalona (Barcelona), Catalonia, Spain
| | - Águeda Prior-Español
- Department of Rheumatology, Hospital Germans Trias i Pujol, Badalona (Barcelona), Catalonia, Spain
| | - Marina Urrutia
- Department of Nephrology, University Hospital Germans Trias i Pujol (HGiTP), Badalona (Barcelona), Catalonia, Spain
- REMAR-IGTP Group, Research Institute Germans Trias i Pujol, Can Ruti Campus, Badalona (Barcelona), Catalonia, Spain
| | - Javier Paul
- Department of Nephrology, University Hospital Germans Trias i Pujol (HGiTP), Badalona (Barcelona), Catalonia, Spain
- REMAR-IGTP Group, Research Institute Germans Trias i Pujol, Can Ruti Campus, Badalona (Barcelona), Catalonia, Spain
| | - Misael C. Bustos
- Department of Nephrology, Pontificia Catholic University of Chile, Santiago, Chile
| | - Anna Vila
- Department of Nephrology, University Hospital Germans Trias i Pujol (HGiTP), Badalona (Barcelona), Catalonia, Spain
- REMAR-IGTP Group, Research Institute Germans Trias i Pujol, Can Ruti Campus, Badalona (Barcelona), Catalonia, Spain
| | - Isa Garnica-León
- Department of Nephrology, Mexican Social Security, IMSS General Hospital of Zone No 2, Tuxtla Gutiérrez, Mexico
| | - Juan F. Navarro-González
- Research Unit and Nephrology Service, University Hospital of Nuestra Señora de la Candelaria, Santa Cruz de Tenerife, Islas Canarias, Spain
- Instituto de Tecnologías Biomédicas, Universidad de la Laguna, Islas Canarias, Spain
| | - Lourdes Mateo
- Department of Rheumatology, Hospital Germans Trias i Pujol, Badalona (Barcelona), Catalonia, Spain
| | - Jordi Bover
- Department of Nephrology, University Hospital Germans Trias i Pujol (HGiTP), Badalona (Barcelona), Catalonia, Spain
- REMAR-IGTP Group, Research Institute Germans Trias i Pujol, Can Ruti Campus, Badalona (Barcelona), Catalonia, Spain
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3
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Kuhn LT, Peng T, Gronowicz G, Hurley MM. Endogenous FGF-2 levels impact FGF-2/BMP-2 growth factor delivery dosing in aged murine calvarial bone defects. J Biomed Mater Res A 2021; 109:2545-2555. [PMID: 34173706 PMCID: PMC9943554 DOI: 10.1002/jbm.a.37249] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Revised: 05/20/2021] [Accepted: 06/11/2021] [Indexed: 12/12/2022]
Abstract
Bone repair in elderly mice has been shown to be improved or negatively impacted by supplementing the highly osteogenic bone morphogenetic protein-2 (BMP-2) with fibroblast growth factor-2 (FGF-2). To better predict the outcome of FGF-2 supplementation, we investigated whether endogenous levels of FGF-2 play a role in optimal dosing of FGF-2 for augmenting BMP-2 activity in elderly mice. In vivo calvarial bone defect studies in Fgf2 knockout mice with wildtype controls were conducted with the growth factors delivered in a highly localized manner from a biomimetic calcium phosphate/polyelectrolyte multilayer coating applied to a bone graft substitute. Endogenous FGF-2 levels were measured in old mice versus young and found to decrease with age. Optimal dosing for improving bone defect repair correlated with levels of endogenous FGF-2, with a larger dose of FGF-2 required to have a positive effect on bone healing in the Fgf2 knockout mice. The same dose in wildtype old mice, with higher levels of FGF-2, promoted chondrogenesis and increased osteoclast activity. The results suggest a personalized medicine approach, based on a knowledge of endogenous levels of FGF-2, should guide FGF-2 supplementation in order to avoid provoking excessive bone resorption and cartilage formation, both of which inhibited calvarial bone repair.
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Affiliation(s)
- Liisa T Kuhn
- Department of Biomedical Engineering, University of Connecticut Health Center, Farmington, Connecticut, USA
| | - Tao Peng
- Department of Biomedical Engineering, University of Connecticut Health Center, Farmington, Connecticut, USA
| | - Gloria Gronowicz
- Department of Surgery, University of Connecticut Health Center, Farmington, Connecticut, USA
| | - Marja M Hurley
- Department of Medicine, University of Connecticut Health Center, Farmington, Connecticut, USA
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4
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Zweifler LE, Koh AJ, Daignault-Newton S, McCauley LK. Anabolic actions of PTH in murine models: two decades of insights. J Bone Miner Res 2021; 36:1979-1998. [PMID: 34101904 PMCID: PMC8596798 DOI: 10.1002/jbmr.4389] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Revised: 05/26/2021] [Accepted: 06/02/2021] [Indexed: 01/19/2023]
Abstract
Parathyroid hormone (PTH) is produced by the parathyroid glands in response to low serum calcium concentrations where it targets bones, kidneys, and indirectly, intestines. The N-terminus of PTH has been investigated for decades for its ability to stimulate bone formation when administered intermittently (iPTH) and is used clinically as an effective anabolic agent for the treatment of osteoporosis. Despite great interest in iPTH and its clinical use, the mechanisms of PTH action remain complicated and not fully defined. More than 70 gene targets in more than 90 murine models have been utilized to better understand PTH anabolic actions. Because murine studies utilized wild-type mice as positive controls, a variety of variables were analyzed to better understand the optimal conditions under which iPTH functions. The greatest responses to iPTH were in male mice, with treatment starting later than 12 weeks of age, a treatment duration lasting 5-6 weeks, and a PTH dose of 30-60 μg/kg/day. This comprehensive study also evaluated these genetic models relative to the bone formative actions with a primary focus on the trabecular compartment revealing trends in critical genes and gene families relevant for PTH anabolic actions. The summation of these data revealed the gene deletions with the greatest increase in trabecular bone volume in response to iPTH. These included PTH and 1-α-hydroxylase (Pth;1α(OH)ase, 62-fold), amphiregulin (Areg, 15.8-fold), and PTH related protein (Pthrp, 10.2-fold). The deletions with the greatest inhibition of the anabolic response include deletions of: proteoglycan 4 (Prg4, -9.7-fold), low-density lipoprotein receptor-related protein 6 (Lrp6, 1.3-fold), and low-density lipoprotein receptor-related protein 5 (Lrp5, -1.0-fold). Anabolic actions of iPTH were broadly affected via multiple and diverse genes. This data provides critical insight for future research and development, as well as application to human therapeutics. © 2021 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR).
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Affiliation(s)
- Laura E Zweifler
- Department of Periodontics and Oral Medicine, University of Michigan School of Dentistry, Ann Arbor, Michigan, USA
| | - Amy J Koh
- Department of Periodontics and Oral Medicine, University of Michigan School of Dentistry, Ann Arbor, Michigan, USA
| | | | - Laurie K McCauley
- Department of Periodontics and Oral Medicine, University of Michigan School of Dentistry, Ann Arbor, Michigan, USA.,Department of Pathology, Medical School, University of Michigan, Ann Arbor, Michigan, USA
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5
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Morimoto A, Kikuta J, Nishikawa K, Sudo T, Uenaka M, Furuya M, Hasegawa T, Hashimoto K, Tsukazaki H, Seno S, Nakamura A, Okuzaki D, Sugihara F, Ninomiya A, Yoshimura T, Takao-Kawabata R, Matsuda H, Ishii M. SLPI is a critical mediator that controls PTH-induced bone formation. Nat Commun 2021; 12:2136. [PMID: 33837198 PMCID: PMC8035405 DOI: 10.1038/s41467-021-22402-x] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2020] [Accepted: 03/12/2021] [Indexed: 12/21/2022] Open
Abstract
Osteoclastic bone resorption and osteoblastic bone formation/replenishment are closely coupled in bone metabolism. Anabolic parathyroid hormone (PTH), which is commonly used for treating osteoporosis, shifts the balance from osteoclastic to osteoblastic, although it is unclear how these cells are coordinately regulated by PTH. Here, we identify a serine protease inhibitor, secretory leukocyte protease inhibitor (SLPI), as a critical mediator that is involved in the PTH-mediated shift to the osteoblastic phase. Slpi is highly upregulated in osteoblasts by PTH, while genetic ablation of Slpi severely impairs PTH-induced bone formation. Slpi induction in osteoblasts enhances its differentiation, and increases osteoblast-osteoclast contact, thereby suppressing osteoclastic function. Intravital bone imaging reveals that the PTH-mediated association between osteoblasts and osteoclasts is disrupted in the absence of SLPI. Collectively, these results demonstrate that SLPI regulates the communication between osteoblasts and osteoclasts to promote PTH-induced bone anabolism.
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Affiliation(s)
- Akito Morimoto
- Department of Immunology and Cell Biology, Graduate School of Medicine and Frontier Biosciences, Osaka University, Osaka, Japan
- WPI-Immunology Frontier Research Center, Osaka University, Osaka, Japan
| | - Junichi Kikuta
- Department of Immunology and Cell Biology, Graduate School of Medicine and Frontier Biosciences, Osaka University, Osaka, Japan.
- WPI-Immunology Frontier Research Center, Osaka University, Osaka, Japan.
- Laboratory of Bioimaging and Drug Discovery, National Institutes of Biomedical Innovation, Health and Nutrition, Osaka, Japan.
| | - Keizo Nishikawa
- Department of Immunology and Cell Biology, Graduate School of Medicine and Frontier Biosciences, Osaka University, Osaka, Japan
- WPI-Immunology Frontier Research Center, Osaka University, Osaka, Japan
| | - Takao Sudo
- Department of Immunology and Cell Biology, Graduate School of Medicine and Frontier Biosciences, Osaka University, Osaka, Japan
- WPI-Immunology Frontier Research Center, Osaka University, Osaka, Japan
| | - Maki Uenaka
- Department of Immunology and Cell Biology, Graduate School of Medicine and Frontier Biosciences, Osaka University, Osaka, Japan
- WPI-Immunology Frontier Research Center, Osaka University, Osaka, Japan
| | - Masayuki Furuya
- Department of Immunology and Cell Biology, Graduate School of Medicine and Frontier Biosciences, Osaka University, Osaka, Japan
- WPI-Immunology Frontier Research Center, Osaka University, Osaka, Japan
| | - Tetsuo Hasegawa
- Department of Immunology and Cell Biology, Graduate School of Medicine and Frontier Biosciences, Osaka University, Osaka, Japan
- WPI-Immunology Frontier Research Center, Osaka University, Osaka, Japan
| | - Kunihiko Hashimoto
- Department of Immunology and Cell Biology, Graduate School of Medicine and Frontier Biosciences, Osaka University, Osaka, Japan
- WPI-Immunology Frontier Research Center, Osaka University, Osaka, Japan
| | - Hiroyuki Tsukazaki
- Department of Immunology and Cell Biology, Graduate School of Medicine and Frontier Biosciences, Osaka University, Osaka, Japan
- WPI-Immunology Frontier Research Center, Osaka University, Osaka, Japan
| | - Shigeto Seno
- Department of Bioinformatic Engineering, Graduate School of Information Science and Technology, Osaka University, Osaka, Japan
| | - Akira Nakamura
- Division of Immunology, Tohoku Medical and Pharmaceutical University, Miyagi, Japan
| | - Daisuke Okuzaki
- WPI-Immunology Frontier Research Center, Osaka University, Osaka, Japan
- Genome Information Research Center, Research Institute for Microbial Diseases, Osaka University, Osaka, Japan
| | - Fuminori Sugihara
- Core Instrumentation Facility, Immunology Frontier Research Center and Research Institute for Microbial Diseases, Osaka University, Osaka, Japan
| | - Akinori Ninomiya
- Core Instrumentation Facility, Immunology Frontier Research Center and Research Institute for Microbial Diseases, Osaka University, Osaka, Japan
| | - Takeshi Yoshimura
- Medical Affairs Department, Asahi Kasei Pharma Corporation, Tokyo, Japan
| | - Ryoko Takao-Kawabata
- Laboratory for Pharmacology, Pharmaceuticals Research Center, Asahi Kasei Pharma Corporation, Tokyo, Japan
| | - Hideo Matsuda
- Department of Bioinformatic Engineering, Graduate School of Information Science and Technology, Osaka University, Osaka, Japan
| | - Masaru Ishii
- Department of Immunology and Cell Biology, Graduate School of Medicine and Frontier Biosciences, Osaka University, Osaka, Japan.
- WPI-Immunology Frontier Research Center, Osaka University, Osaka, Japan.
- Laboratory of Bioimaging and Drug Discovery, National Institutes of Biomedical Innovation, Health and Nutrition, Osaka, Japan.
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6
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Physical Activity-Dependent Regulation of Parathyroid Hormone and Calcium-Phosphorous Metabolism. Int J Mol Sci 2020; 21:ijms21155388. [PMID: 32751307 PMCID: PMC7432834 DOI: 10.3390/ijms21155388] [Citation(s) in RCA: 47] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2020] [Revised: 07/09/2020] [Accepted: 07/23/2020] [Indexed: 12/14/2022] Open
Abstract
Exercise perturbs homeostasis, alters the levels of circulating mediators and hormones, and increases the demand by skeletal muscles and other vital organs for energy substrates. Exercise also affects bone and mineral metabolism, particularly calcium and phosphate, both of which are essential for muscle contraction, neuromuscular signaling, biosynthesis of adenosine triphosphate (ATP), and other energy substrates. Parathyroid hormone (PTH) is involved in the regulation of calcium and phosphate homeostasis. Understanding the effects of exercise on PTH secretion is fundamental for appreciating how the body adapts to exercise. Altered PTH metabolism underlies hyperparathyroidism and hypoparathyroidism, the complications of which affect the organs involved in calcium and phosphorous metabolism (bone and kidney) and other body systems as well. Exercise affects PTH expression and secretion by altering the circulating levels of calcium and phosphate. In turn, PTH responds directly to exercise and exercise-induced myokines. Here, we review the main concepts of the regulation of PTH expression and secretion under physiological conditions, in acute and chronic exercise, and in relation to PTH-related disorders.
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7
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Abstract
Parathyroid hormone is an essential regulator of extracellular calcium and phosphate. PTH enhances calcium reabsorption while inhibiting phosphate reabsorption in the kidneys, increases the synthesis of 1,25-dihydroxyvitamin D, which then increases gastrointestinal absorption of calcium, and increases bone resorption to increase calcium and phosphate. Parathyroid disease can be an isolated endocrine disorder or part of a complex syndrome. Genetic mutations can account for diseases of parathyroid gland formulation, dysregulation of parathyroid hormone synthesis or secretion, and destruction of the parathyroid glands. Over the years, a number of different options are available for the treatment of different types of parathyroid disease. Therapeutic options include surgical removal of hypersecreting parathyroid tissue, administration of parathyroid hormone, vitamin D, activated vitamin D, calcium, phosphate binders, calcium-sensing receptor, and vitamin D receptor activators to name a few. The accurate assessment of parathyroid hormone also provides essential biochemical information to properly diagnose parathyroid disease. Currently available immunoassays may overestimate or underestimate bioactive parathyroid hormone because of interferences from truncated parathyroid hormone fragments, phosphorylation of parathyroid hormone, and oxidation of amino acids of parathyroid hormone.
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Affiliation(s)
- Edward Ki Yun Leung
- Department of Pathology and Laboratory Medicine, Children's Hospital Los Angeles, Los Angeles, CA, United States; Department of Pathology, Keck School of Medicine of University of Southern California, Los Angeles, CA, United States.
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8
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Abstract
Parathyroid hormone (PTH) is the major secretory product of the parathyroid glands, and in hypocalcemic conditions, can enhance renal calcium reabsorption, increase active vitamin D production to increase intestinal calcium absorption, and mobilize calcium from bone by increasing turnover, mainly but not exclusively in cortical bone. PTH has therefore found clinical use as replacement therapy in hypoparathyroidism. PTH also may have a physiologic role in augmenting bone formation, particularly in trabecular and to some extent in cortical bone. This action has been applied to the clinic to provide anabolic therapy for osteoporosis.
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Affiliation(s)
- David Goltzman
- Department of Medicine and Research Institute of the McGill University Health Centre, 1001 Decarie Boulevard, Montreal, Quebec H4A 3J1, Canada; Departments of Medicine and of Physiology, McGill University, 845 Sherbrooke St West, Montreal, Quebec H3A 0B9, Canada.
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9
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Xiao L, Fei Y, Hurley MM. FGF2 crosstalk with Wnt signaling in mediating the anabolic action of PTH on bone formation. Bone Rep 2018; 9:136-144. [PMID: 30258857 PMCID: PMC6152810 DOI: 10.1016/j.bonr.2018.09.003] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/09/2018] [Revised: 07/30/2018] [Accepted: 09/20/2018] [Indexed: 12/20/2022] Open
Abstract
The mechanisms of the anabolic effect of parathyroid hormone (PTH) in bone are not fully defined. The bone anabolic effects of PTH require fibroblast growth factor 2 (FGF2) as well as Wnt signaling and FGF2 modulates Wnt signaling in osteoblasts. In vivo PTH administration differentially modulated Wnt signaling in bones of wild type (WT) and in mice that Fgf2 was knocked out (Fgf2KO). PTH increased Wnt10b mRNA and protein in WT but not in KO mice. Wnt antagonist SOST mRNA and protein was significantly higher in KO group. However, PTH decreased Sost mRNA significantly in WT as well as in Fgf2KO mice, but to a lesser extent in Fgf2KO. Dickhopf 2 (DKK2) is critical for osteoblast mineralization. PTH increased Dkk2 mRNA in WT mice but the response was impaired in Fgf2KO mice. PTH significantly increased Lrp5 mRNA and phosphorylation of Lrp6 in WT but the increase was markedly attenuated in Fgf2KO mice. PTH increased β-catenin expression and Wnt/β-catenin transcriptional activity significantly in WT but not in Fgf2KO mice. These data suggest that the impaired bone anabolic response to PTH in Fgf2KO mice is partially mediated by attenuated Wnt signaling. In vivo PTH administration differentially modulated Wnt signaling in bones of WT and Fgf2KO mice. PTH treatment increased WNT10b and DKK2 expression in WT mice but the increase was blunted in Fgf2KO mice PTH increased Lrp5 mRNA and phosphorylation of Lrp6 in WT but the increase was markedly attenuated in Fgf2KO mice. PTH treatment increased β-catenin protein level and Wnt/β-catenin transcriptional activity in WT but not in Fgf2KO mice The impaired bone anabolic response to PTH in Fgf2KO mice is partially mediated by attenuated Wnt signaling.
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Affiliation(s)
| | | | - Marja M. Hurley
- Corresponding author at: Department of Medicine, University of Connecticut Health Center, 263 Farmington Ave., Farmington, CT 06030, USA.
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10
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Wein MN, Kronenberg HM. Regulation of Bone Remodeling by Parathyroid Hormone. Cold Spring Harb Perspect Med 2018; 8:cshperspect.a031237. [PMID: 29358318 DOI: 10.1101/cshperspect.a031237] [Citation(s) in RCA: 130] [Impact Index Per Article: 21.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Parathyroid hormone (PTH) exerts profound effects on skeletal homeostasis through multiple cellular and molecular mechanisms. Continuous hyperparathyroidism causes net loss of bone mass, despite accelerating bone formation by osteoblasts. Intermittent treatment with PTH analogs represents the only Food and Drug Administration (FDA)-approved bone anabolic osteoporosis treatment strategy. Functional PTH receptors are present on cells of the osteoblast lineage, ranging from early skeletal stem cells to matrix-embedded osteocytes. In addition, bone remodeling by osteoclasts liberates latent growth factors present within bone matrix. Here, we will provide an overview of the multiple cellular and molecular mechanisms through which PTH influences bone homeostasis. Notably, net skeletal effects of continuous versus intermittent can differ significantly. Where possible, we will highlight mechanisms through which continuous hyperparathyroidism leads to bone loss, and through which intermittent hyperparathyroidism boosts bone mass. Given the therapeutic usage of intermittent PTH (iPTH) treatment for osteoporosis, particular attention will be paid toward mechanisms underlying the bone anabolic effects of once daily PTH administration.
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Affiliation(s)
- Marc N Wein
- Endocrine Unit, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts 02114
| | - Henry M Kronenberg
- Endocrine Unit, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts 02114
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11
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Coffin JD, Homer-Bouthiette C, Hurley MM. Fibroblast Growth Factor 2 and Its Receptors in Bone Biology and Disease. J Endocr Soc 2018; 2:657-671. [PMID: 29942929 PMCID: PMC6009610 DOI: 10.1210/js.2018-00105] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/16/2018] [Accepted: 05/23/2018] [Indexed: 01/24/2023] Open
Abstract
The fibroblast growth factor (FGF) regulatory axis is phylogenetically ancient, evolving into a large mammalian/human gene family of 22 ligands that bind to four receptor tyrosine kinases for a complex physiologic system controlling cell growth, differentiation, and metabolism. The tissue targets for the primary FGF function are mainly in cartilage and in bone for morphogenesis, mineralization, and metabolism. A multitude of complexities in the FGF ligand-receptor signaling pathways have made translation into therapies for FGF-related bone disorders such as osteomalacia, osteoarthritis, and osteoporosis difficult but not impossible.
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Affiliation(s)
| | | | - Marja Marie Hurley
- Department of Medicine, University of Connecticut School of Medicine, UCONN Health, Farmington, Connecticut
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12
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Corrado A, Sanpaolo ER, Di Bello S, Cantatore FP. Osteoblast as a target of anti-osteoporotic treatment. Postgrad Med 2017; 129:858-865. [PMID: 28770650 DOI: 10.1080/00325481.2017.1362312] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Osteoblasts are mesenchymal cells that play a key role in maintaining bone homeostasis; they are responsible for the production of extracellular matrix proteins, regulation of matrix mineralization, control of bone remodeling and regulate osteoclast differentiation. Osteoblasts have an essential role in the pathogenesis of many bone diseases, particularly osteoporosis. For many decades, the main current available treatments for osteoporosis have been represented by anti-resorptive drugs, such as bisphosphonates, which act mainly by inhibiting osteoclasts maturation, proliferation and activity; nevertheless, in recent years much attention has been paid on anabolic aspects of osteoporosis treatment. Many experimental evidences support the hypothesis of direct effects of the classical anti-resorptive drugs also on osteoblasts, and recent progress in understanding bone physiology have led to the development of new pharmacological agents such as anti-sclerostin antibodies and teriparatide which directly target osteoblasts, inducing anabolic effects and promoting bone formation.
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Affiliation(s)
- Addolorata Corrado
- a Rheumatology Clinic Department of Medical and Surgical Sciences , University of Foggia , Foggia , Italy
| | - Eliana Rita Sanpaolo
- a Rheumatology Clinic Department of Medical and Surgical Sciences , University of Foggia , Foggia , Italy
| | - Silvana Di Bello
- a Rheumatology Clinic Department of Medical and Surgical Sciences , University of Foggia , Foggia , Italy
| | - Francesco Paolo Cantatore
- a Rheumatology Clinic Department of Medical and Surgical Sciences , University of Foggia , Foggia , Italy
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13
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PTH[1-34] improves the effects of core decompression in early-stage steroid-associated osteonecrosis model by enhancing bone repair and revascularization. PLoS One 2017; 12:e0178781. [PMID: 28562696 PMCID: PMC5451136 DOI: 10.1371/journal.pone.0178781] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2016] [Accepted: 05/18/2017] [Indexed: 12/31/2022] Open
Abstract
Steroid-associated osteonecrosis (SAON) might induce bone collapse and subsequently lead to joint arthroplasty. Core decompression (CD) is regarded as an effective therapy for early-stage SAON, but the prognosis is unsatisfactory due to incomplete bone repair. Parathyroid hormone[1–34] (PTH[1–34]) has demonstrated positive efficacy in promoting bone formation. We therefore evaluated the effects of PTH on improving the effects of CD in Early-Stage SAON. Distal femoral CD was performed two weeks after osteonecrosis induction or vehicle injection, with ten of the ON-induced rabbits being subjected to six-week PTH[1–34] treatment and the others, including ON-induced and non-induced rabbits, being treated with vehicle. MRI confirmed that intermittent PTH administration improved SAON after CD therapy. Micro-CT showed increased bone formation within the tunnel. Bone repair was enhanced with decreased empty osteocyte lacunae and necrosis foci area, resulting in enhanced peak load and stiffness of the tunnel. Additionally, PTH enlarged the mean diameter of vessels in the marrow and increased the number of vessels within the tunnels, as well as elevated the expression of BMP-2, RUNX2, IGF-1, bFGF and VEGF, together with serum OCN and VEGF levels. Therefore, PTH[1–34] enhances the efficacy of CD on osteogenesis and neovascularization, thus promoting bone and blood vessels repair in the SAON model.
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Xie Y, Yi L, Weng T, Huang J, Luo F, Jiang W, Xian CJ, Du X, Chen L. Fibroblast Growth Factor Receptor 3 Deficiency Does Not Impair the Osteoanabolic Action of Parathyroid Hormone on Mice. Int J Biol Sci 2016; 12:990-9. [PMID: 27489502 PMCID: PMC4971737 DOI: 10.7150/ijbs.14077] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2015] [Accepted: 04/18/2016] [Indexed: 01/14/2023] Open
Abstract
Summary: PTH stimulates bone formation in Fgfr3 knockout mice through promotion of proliferation and differentiation in osteoblasts. Introduction: Previous studies showed that endogenous fibroblast growth factor 2 (FGF-2) is required for parathyroid hormone (PTH)-stimulated bone anabolic effects, however, the exact mechanisms by which PTH stimulate bone formation and the function of FGF receptors in mediating these actions are not fully defined. FGF receptor 3 (FGFR3) has been characterized as an important regulator of bone metabolism and is confirmed to cross-talk with PTH/PTHrP signal in cartilage and bone development. Methods: Fgfr3 knockout and wild-type mice at 2-month-old and 4-month-old were intraperitoneally injected with PTH intermittently for 4 weeks and then the skeletal responses to PTH were assessed by dual energy X-ray absorptiometry (DEXA), micro-computed tomography (μCT) and bone histomorphometry. Results: Intermittent PTH treatment improved bone mineral density (BMD) and femoral mechanical properties in both Fgfr3-/- and wild-type mice. Histomorphometric analysis showed that bone formation and bone resorption were increased in both genotypes following PTH treatment. PTH treatment increased trabecular bone volume (BV/TV) in WT and Fgfr3-deficient mice. The anabolic response in Fgfr3-deficient and wild-type bone is characterized by an increase of both bone formation and resorption-related genes following PTH treatment. In addition, we found that Fgfr3 null osteoblasts (compared to wild-type controls) maintained normal abilities to response to PTH-stimulated increase of proliferation, differentiation, expression of osteoblastic marker genes (Cbfa1, Osteopontin and Osteocalcin), and phosphorylation of Erk1/2. Conclusions: Bone anabolic effects of PTH were not impaired by the absence of FGFR3, suggesting that the FGFR3 signaling may not be required for osteoanabolic effects of PTH activities.
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Affiliation(s)
- Yangli Xie
- 1. Center of Bone Metabolism and Repair, Department of Rehabilitation Medicine, State Key Laboratory of Trauma, Burns and Combined injury, Trauma Center, Research Institute of Surgery, Daping Hospital, Third Military Medical University, Chongqing 400042, China
| | - Lingxian Yi
- 1. Center of Bone Metabolism and Repair, Department of Rehabilitation Medicine, State Key Laboratory of Trauma, Burns and Combined injury, Trauma Center, Research Institute of Surgery, Daping Hospital, Third Military Medical University, Chongqing 400042, China;; 3. Intensive Care Unit, The 306th hospital of PLA, Beijing 100101, China
| | - Tujun Weng
- 1. Center of Bone Metabolism and Repair, Department of Rehabilitation Medicine, State Key Laboratory of Trauma, Burns and Combined injury, Trauma Center, Research Institute of Surgery, Daping Hospital, Third Military Medical University, Chongqing 400042, China
| | - Junlan Huang
- 1. Center of Bone Metabolism and Repair, Department of Rehabilitation Medicine, State Key Laboratory of Trauma, Burns and Combined injury, Trauma Center, Research Institute of Surgery, Daping Hospital, Third Military Medical University, Chongqing 400042, China
| | - Fengtao Luo
- 1. Center of Bone Metabolism and Repair, Department of Rehabilitation Medicine, State Key Laboratory of Trauma, Burns and Combined injury, Trauma Center, Research Institute of Surgery, Daping Hospital, Third Military Medical University, Chongqing 400042, China
| | - Wanling Jiang
- 1. Center of Bone Metabolism and Repair, Department of Rehabilitation Medicine, State Key Laboratory of Trauma, Burns and Combined injury, Trauma Center, Research Institute of Surgery, Daping Hospital, Third Military Medical University, Chongqing 400042, China
| | - Cory J Xian
- 2. Sansom Institute for Health Research, School of Pharmacy and Medical Sciences, University of South Australia, Adelaide, SA 5001, Australia
| | - Xiaolan Du
- 1. Center of Bone Metabolism and Repair, Department of Rehabilitation Medicine, State Key Laboratory of Trauma, Burns and Combined injury, Trauma Center, Research Institute of Surgery, Daping Hospital, Third Military Medical University, Chongqing 400042, China
| | - Lin Chen
- 1. Center of Bone Metabolism and Repair, Department of Rehabilitation Medicine, State Key Laboratory of Trauma, Burns and Combined injury, Trauma Center, Research Institute of Surgery, Daping Hospital, Third Military Medical University, Chongqing 400042, China
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15
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Lau KHW, Chen ST, Wang X, Mohan S, Wergedal JE, Kesavan C, Srivastava AK, Gridley DS, Hall SL. Opposing effects of Sca-1(+) cell-based systemic FGF2 gene transfer strategy on lumbar versus caudal vertebrae in the mouse. Gene Ther 2016; 23:500-9. [PMID: 26934099 PMCID: PMC4891288 DOI: 10.1038/gt.2016.21] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2015] [Revised: 02/09/2016] [Accepted: 02/26/2016] [Indexed: 01/24/2023]
Abstract
Our previous work showed that a Sca-1+ cell-based FGF2 therapy was capable of promoting robust increases in trabecular bone formation and connectivity on the endosteum of long bones. Past work reported that administration of FGF2 protein promoted bone formation in red marrow but not in yellow marrow. The issue as to whether the Sca-1+ cell-based FGF2 therapy is effective in yellow marrow is highly relevant to its clinical potential for osteoporosis, as most red marrows in a person of an advanced age, are converted to yellow marrows. Accordingly, this study sought to compare the osteogenic effects of this stem cell-based FGF2 therapy on red marrow-filled lumbar vertebrae with those on yellow marrow-filled caudal vertebrae of young adult W41/W41 mice. The Sca-1+ cell-based FGF2 therapy drastically increased trabecular bone formation in lumbar vertebrae, but the therapy not only did not promote bone formation but instead caused substantial loss of trabecular bone in caudal vertebrae. The lack of an osteogenic response was not due to insufficient engraftment of FGF2-expressing Sca-1+ cells or inadequate FGF2 expression in caudal vertebrae. Previous studies have demonstrated that recipient mice of this stem cell-based FGF2 therapy developed secondary hyperparathyroidism and increased bone resorption. Thus, the loss of bone mass in caudal vertebrae might in part be due to an increase in resorption without a corresponding increase in bone formation. In conclusion, the Sca-1+ cell-based FGF2 therapy is osteogenic in red marrow but not in yellow marrow.
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Affiliation(s)
- K-H W Lau
- Musculoskeletal Disease Center, Jerry L. Pettis Memorial VA Medical Center, Loma Linda, CA, USA
| | - S-T Chen
- Musculoskeletal Disease Center, Jerry L. Pettis Memorial VA Medical Center, Loma Linda, CA, USA
| | - X Wang
- Musculoskeletal Disease Center, Jerry L. Pettis Memorial VA Medical Center, Loma Linda, CA, USA
| | - S Mohan
- Musculoskeletal Disease Center, Jerry L. Pettis Memorial VA Medical Center, Loma Linda, CA, USA
| | - J E Wergedal
- Musculoskeletal Disease Center, Jerry L. Pettis Memorial VA Medical Center, Loma Linda, CA, USA
| | - C Kesavan
- Musculoskeletal Disease Center, Jerry L. Pettis Memorial VA Medical Center, Loma Linda, CA, USA
| | - A K Srivastava
- Laboratory of Human Toxicology, Pharmacology, Applied/Developmental Research Directorate, SAIC-Frederick, Frederick National Laboratory for Cancer Research, Frederick, MD, USA
| | - D S Gridley
- Department of Radiation Medicine, Loma Linda University School of Medicine, Loma Linda, CA, USA
| | - S L Hall
- Musculoskeletal Disease Center, Jerry L. Pettis Memorial VA Medical Center, Loma Linda, CA, USA
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Sankaran JS, Li B, Donahue LR, Judex S. Modulation of unloading-induced bone loss in mice with altered ERK signaling. Mamm Genome 2015; 27:47-61. [PMID: 26546009 DOI: 10.1007/s00335-015-9611-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2015] [Accepted: 10/27/2015] [Indexed: 12/31/2022]
Abstract
Genetic variations mediate skeletal responsiveness to mechanical unloading, with individual space travelers exhibiting large variations in the extent of bone loss. We previously identified genomic regions harboring several hundred genes that can modulate the magnitude of skeletal adaptation to mechanical unloading. Here, bioinformatic filters aided in shortlisting 30 genes with bone-related and mechanoregulatory roles. The genes CD44, FGF2, NOD2, and Fas, all associated with ERK signaling, were then functionally tested in hindlimb-unloaded (HLU) knockout (KO) mice. Compared to their respective normally ambulating wildtype (WT) controls, all KO strains, except Fas mice, had lower trabecular bone volume, bone volume fraction, and/or trabecular number. For cortical bone and compared to ambulatory WT mice, CD44(-/-) had impaired properties while FGF2(-/-) showed enhanced indices. NOD2(-/-) and Fas(-/-) did not have a cortical phenotype. In all KO and WT groups, HLU resulted in impaired trabecular and cortical indices, primarily due to trabecular tissue loss and mitigation of cortical bone growth. The difference in trabecular separation between HLU and ambulatory controls was significantly greater in CD44(-/-) and NOD2(-/-) mice than in WT mice. In cortical bone, differences in cortical thickness, total pore volume, and cortical porosity between HLU and controls were aggravated in CD44(-/-) mice. In contrast, deletion of NOD2 and Fas genes mitigated the differences in Po.V between HLU and control mice. Together, we narrowed a previous list of QTL-derived candidate genes from over 300 to 30, and showed that CD44, NOD2, and Fas have distinct functions in regulating changes in trabecular and cortical bone indices during unloading.
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Affiliation(s)
- Jeyantt S Sankaran
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY, 11794-5281, USA
| | - Bing Li
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY, 11794-5281, USA.,Department of Orthopedics, Tianjin Hospital, Tianjin, 300211, China
| | | | - Stefan Judex
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY, 11794-5281, USA.
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17
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Zhang L, Chen P, Chen L, Weng T, Zhang S, Zhou X, Zhang B, Liu L. Inhibited Wnt signaling causes age-dependent abnormalities in the bone matrix mineralization in the Apert syndrome FGFR2(S252W/+) mice. PLoS One 2015; 10:e112716. [PMID: 25693202 PMCID: PMC4333342 DOI: 10.1371/journal.pone.0112716] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2014] [Accepted: 10/14/2014] [Indexed: 01/16/2023] Open
Abstract
Apert syndrome (AS) is a type of autosomal dominant disease characterized by premature fusion of the cranial sutures, severe syndactyly, and other abnormalities in internal organs. Approximately 70% of AS cases are caused by a single mutation, S252W, in fibroblast growth factor receptor 2 (FGFR2). Two groups have generated FGFR2 knock-in mice Fgfr2S252W/+ that exhibit features of AS. During the present study of AS using the Fgfr2S252W/+ mouse model, an age-related phenotype of bone homeostasis was discovered. The long bone mass was lower in 2 month old mutant mice than in age-matched controls but higher in 5 month old mutant mice. This unusual phenotype suggested that bone marrow-derived mesenchymal stem cells (BMSCs), which are vital to maintain bone homeostasis, might be involved. BMSCs were isolated from Fgfr2S252W/+ mice and found that S252W mutation could impair osteogenic differentiation BMSCs but enhance mineralization of more mature osteoblasts. A microarray analysis revealed that Wnt pathway inhibitors SRFP1/2/4 were up-regulated in mutant BMSCs. This work provides evidence to show that the Wnt/β-catenin pathway is inhibited in both mutant BMSCs and osteoblasts, and differentiation defects of these cells can be ameliorated by Wnt3a treatment. The present study suggested that the bone abnormalities caused by deregulation of Wnt pathway may underlie the symptoms of AS.
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Affiliation(s)
- Li Zhang
- Department of Stomatology, Daping Hospital & Research Institute of Surgery, Third Military Medical University, Chongqing 400042, China
- Department 4, Daping Hospital & Research Institute of Surgery, Third Military Medical University, State Key Laboratory of Trauma, Burns and Combined Injury, Chongqing 400042, China
| | - Peng Chen
- Department 4, Daping Hospital & Research Institute of Surgery, Third Military Medical University, State Key Laboratory of Trauma, Burns and Combined Injury, Chongqing 400042, China
- Neurosurgery Department, PLA 324 Hospital, Chongqing, China
| | - Lin Chen
- Department of Stomatology, Daping Hospital & Research Institute of Surgery, Third Military Medical University, Chongqing 400042, China
| | - Tujun Weng
- Department 4, Daping Hospital & Research Institute of Surgery, Third Military Medical University, State Key Laboratory of Trauma, Burns and Combined Injury, Chongqing 400042, China
| | - Shichang Zhang
- Department 4, Daping Hospital & Research Institute of Surgery, Third Military Medical University, State Key Laboratory of Trauma, Burns and Combined Injury, Chongqing 400042, China
| | - Xia Zhou
- Department of Stomatology, Daping Hospital & Research Institute of Surgery, Third Military Medical University, Chongqing 400042, China
| | - Bo Zhang
- Department 4, Daping Hospital & Research Institute of Surgery, Third Military Medical University, State Key Laboratory of Trauma, Burns and Combined Injury, Chongqing 400042, China
| | - Luchuan Liu
- Department of Stomatology, Daping Hospital & Research Institute of Surgery, Third Military Medical University, Chongqing 400042, China
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18
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Dong SS, Yang TL, Yan H, Rong ZQ, Chen JB, Hao RH, Chen XF, Guo Y. Association analyses of FGFR2 gene polymorphisms with femoral neck bone mineral density in Chinese Han population. Mol Genet Genomics 2014; 290:485-91. [PMID: 25300516 DOI: 10.1007/s00438-014-0936-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2014] [Accepted: 09/30/2014] [Indexed: 12/26/2022]
Abstract
Femoral neck (FN) bone mineral density (BMD) is the most important risk phenotype for osteoporosis and has been used as a reference standard for describing osteoporosis. Identification of genetic variations associated with FN BMD may provide potential targets for therapeutic studies. Given the important biological role of FGFR2 gene involved in bone, we tested the associations between FGFR2 polymorphisms and FN BMD in 1,300 Chinese Han subjects. Of the 28 total SNPs, 2 SNPs, namely rs11200014 and rs1078806, were significantly associated with FN BMD under dominant model (P = 0.0014 and 0.0012, respectively) after conservative Bonferroni correction. The two SNPs were in complete linkage disequilibrium. In addition, haplotype-based association tests identified two haplotypes significantly associated with FN BMD, including one haplotype in block 4 where the two SNPs located. However, different from previous studies in white older men, we did not detect any significant association in sex-stratified analyses. In summary, our findings suggest that the FGFR2 gene may play an important role in variation in FN BMD in Chinese Han population, independent of gender effects. Further studies performed in multiple and large samples are needed to elucidate the underlying molecular mechanism and pathophysiology of osteoporosis.
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Affiliation(s)
- Shan-Shan Dong
- Key Laboratory of Biomedical Information Engineering of Ministry of Education, and Institute of Molecular Genetics, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an, 710049, People's Republic of China
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Xie Y, Zhou S, Chen H, Du X, Chen L. Recent research on the growth plate: Advances in fibroblast growth factor signaling in growth plate development and disorders. J Mol Endocrinol 2014; 53:T11-34. [PMID: 25114206 DOI: 10.1530/jme-14-0012] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Skeletons are formed through two distinct developmental actions, intramembranous ossification and endochondral ossification. During embryonic development, most bone is formed by endochondral ossification. The growth plate is the developmental center for endochondral ossification. Multiple signaling pathways participate in the regulation of endochondral ossification. Fibroblast growth factor (FGF)/FGF receptor (FGFR) signaling has been found to play a vital role in the development and maintenance of growth plates. Missense mutations in FGFs and FGFRs can cause multiple genetic skeletal diseases with disordered endochondral ossification. Clarifying the molecular mechanisms of FGFs/FGFRs signaling in skeletal development and genetic skeletal diseases will have implications for the development of therapies for FGF-signaling-related skeletal dysplasias and growth plate injuries. In this review, we summarize the recent advances in elucidating the role of FGFs/FGFRs signaling in growth plate development, genetic skeletal disorders, and the promising therapies for those genetic skeletal diseases resulting from FGFs/FGFRs dysfunction. Finally, we also examine the potential important research in this field in the future.
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Affiliation(s)
- Yangli Xie
- Department of Rehabilitation MedicineCenter of Bone Metabolism and Repair, Trauma Center, State Key Laboratory of Trauma, Burns and Combined Injury, Institute of Surgery Research, Daping Hospital, Third Military Medical University, Chongqing 400042, China
| | - Siru Zhou
- Department of Rehabilitation MedicineCenter of Bone Metabolism and Repair, Trauma Center, State Key Laboratory of Trauma, Burns and Combined Injury, Institute of Surgery Research, Daping Hospital, Third Military Medical University, Chongqing 400042, China
| | - Hangang Chen
- Department of Rehabilitation MedicineCenter of Bone Metabolism and Repair, Trauma Center, State Key Laboratory of Trauma, Burns and Combined Injury, Institute of Surgery Research, Daping Hospital, Third Military Medical University, Chongqing 400042, China
| | - Xiaolan Du
- Department of Rehabilitation MedicineCenter of Bone Metabolism and Repair, Trauma Center, State Key Laboratory of Trauma, Burns and Combined Injury, Institute of Surgery Research, Daping Hospital, Third Military Medical University, Chongqing 400042, China
| | - Lin Chen
- Department of Rehabilitation MedicineCenter of Bone Metabolism and Repair, Trauma Center, State Key Laboratory of Trauma, Burns and Combined Injury, Institute of Surgery Research, Daping Hospital, Third Military Medical University, Chongqing 400042, China
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Chen M, Qiao H, Su Z, Li H, Ping Q, Zong L. Emerging therapeutic targets for osteoporosis treatment. Expert Opin Ther Targets 2014; 18:817-31. [PMID: 24766518 DOI: 10.1517/14728222.2014.912632] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
INTRODUCTION To date, osteoporosis still remains a major public health burden especially for the aging populations. Over the last few decades treatments for osteoporosis have largely focused on anti-resorptive agents represented by bisphosphonates and estrogen therapy that dominated the market. Unsatisfactory efficacy, non-specificity and long-term safety of current therapies necessitate the need for new targets effectively preventing and treating of osteoporosis. AREAS COVERED This review expatiates on the mechanism of osteoporosis occurrence and bone remodeling cycle in detail. New targets of antiresorptive and anabolic agents based on the functions of osteoblasts and osteoclasts as well as associated signaling pathways are outlined. EXPERT OPINION Advanced understanding in the fields of bone remodeling, functions of osteoblasts, osteoclasts and osteocytes associated with osteoporosis occurrence offers the emerging bone-resorptive or bone-formative targets. Currently, molecules involving RANK-RANKL-OPG system and Wnt/β-catenin signaling pathway act as the most promising targets.
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Affiliation(s)
- Minglei Chen
- China Pharmaceutical University, Key Lab of State Natural Medicine, Department of Pharmaceutics , Nanjing 210009 , PR China +86 25 83271092; +86 25 83271317 ; +86 25 83271092; +86 25 83271317 ; ;
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21
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Campbell GM, Tiwari S, Grundmann F, Purcz N, Schem C, Glüer CC. Three-dimensional image registration improves the long-term precision of in vivo micro-computed tomographic measurements in anabolic and catabolic mouse models. Calcif Tissue Int 2014; 94:282-92. [PMID: 24170302 DOI: 10.1007/s00223-013-9809-4] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/09/2013] [Accepted: 10/13/2013] [Indexed: 11/24/2022]
Abstract
Micro-computed tomography (micro-CT) is a widely used technique to track bone structural and mineral changes in small animals in vivo. Precise definition of volumes of interest (VOIs) in follow-up scans is required to accurately quantify these changes. To improve precision, VOIs can be transferred from baseline images onto follow-ups using image registration. We studied the performance of a registration procedure applied to in vivo data sets of anabolic and osteoporotic bone changes in mice. Micro-CT image data from two separate CD1 mouse data sets were studied. The first included a group treated with parathyroid hormone (PTH) and control and the second, an ovariectomy (OVX) group and control. Micro-CT was performed once per week for 4 weeks at the proximal tibia starting at treatment onset (PTH data set) or after surgery (OVX data set). A series consisting entirely of user-defined VOIs and a registered series where VOIs defined at baseline were transferred to follow-ups were created. Standard bone structural and mineral measurements were calculated. Image registration resulted in a 13-56 % reduction in precision error. Significant effects of registration to detect PTH-induced changes in BV/TV and trabecular BMD were observed. When changes were very pronounced or small, the qualitative improvement observed for the registered data set did not reach statistical significance. This study documents an increase in long-term precision of micro-CT measurements with image registration. Sensitivity to detect changes was improved but not uniform for all parameters. Future study of this technique on images with a smaller voxel size (<19 μm) may capture the effect in greater detail, in particular for trabecular thickness, where changes may be too small to be observed with the voxel size used here. Our results document the value of registration and indicate that the magnitude of improvement depends on the model and treatment chosen.
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Affiliation(s)
- Graeme M Campbell
- Department of Radiology, University Hospital Schleswig-Holstein, Campus Kiel, Kiel, Germany,
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22
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Chen P, Zhang L, Weng T, Zhang S, Sun S, Chang M, Li Y, Zhang B, Zhang L. A Ser252Trp mutation in fibroblast growth factor receptor 2 (FGFR2) mimicking human Apert syndrome reveals an essential role for FGF signaling in the regulation of endochondral bone formation. PLoS One 2014; 9:e87311. [PMID: 24489893 PMCID: PMC3904987 DOI: 10.1371/journal.pone.0087311] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2013] [Accepted: 12/20/2013] [Indexed: 01/07/2023] Open
Abstract
A S252W mutation of fibroblast growth factor receptor 2 (FGFR2), which is responsible for nearly two-thirds of Apert syndrome (AS) cases, causes retarded development of the skeleton and skull malformation resulting from premature fusion of the craniofacial sutures. We utilized a Fgfr2+/S252W mouse (a knock-in mouse model mimicking human AS) to demonstrate decreased bone mass due to reduced trabecular bone volume, reduced bone mineral density, and shortened growth plates in the long bones. In vitro bone mesenchymal stem cells (BMSCs) culture studies revealed that the mutant mice showed reduced BMSC proliferation, a reduction in chondrogenic differentiation, and reduced mineralization. Our results suggest that these phenomena are caused by up-regulation of p38 and Erk1/2 phosphorylation. Treatment of cultured mutant bone rudiments with SB203580 or PD98059 resulted in partial rescue of the bone growth retardation. The p38 signaling pathway especially was found to be responsible for the retarded long bone development. Our data indicate that the S252W mutation in FGFR2 directly affects endochondral ossification, resulting in growth retardation of the long bone. We also show that the p38 and Erk1/2 signaling pathways partially mediate the effects of the S252W mutation of FGFR2 on long bone development.
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Affiliation(s)
- Peng Chen
- State Key Laboratory of Trauma, Burns and Combined Injury, Institute of Surgery Research, Daping Hospital, Third Military Medical University, Chongqing, China
- Neurosurgery Department, PLA 324 Hospital, Chongqing, China
| | - Li Zhang
- State Key Laboratory of Trauma, Burns and Combined Injury, Institute of Surgery Research, Daping Hospital, Third Military Medical University, Chongqing, China
| | - Tujun Weng
- State Key Laboratory of Trauma, Burns and Combined Injury, Institute of Surgery Research, Daping Hospital, Third Military Medical University, Chongqing, China
| | - Shichang Zhang
- State Key Laboratory of Trauma, Burns and Combined Injury, Institute of Surgery Research, Daping Hospital, Third Military Medical University, Chongqing, China
| | - Shijin Sun
- State Key Laboratory of Trauma, Burns and Combined Injury, Institute of Surgery Research, Daping Hospital, Third Military Medical University, Chongqing, China
| | - Mingtao Chang
- State Key Laboratory of Trauma, Burns and Combined Injury, Institute of Surgery Research, Daping Hospital, Third Military Medical University, Chongqing, China
| | - Yang Li
- State Key Laboratory of Trauma, Burns and Combined Injury, Institute of Surgery Research, Daping Hospital, Third Military Medical University, Chongqing, China
| | - Bo Zhang
- State Key Laboratory of Trauma, Burns and Combined Injury, Institute of Surgery Research, Daping Hospital, Third Military Medical University, Chongqing, China
- * E-mail: (BZ); (Lianyang Zhang)
| | - Lianyang Zhang
- State Key Laboratory of Trauma, Burns and Combined Injury, Institute of Surgery Research, Daping Hospital, Third Military Medical University, Chongqing, China
- * E-mail: (BZ); (Lianyang Zhang)
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Fibroblast growth factor signaling promotes physiological bone remodeling and stem cell self-renewal. Curr Opin Hematol 2013; 20:237-44. [PMID: 23567340 DOI: 10.1097/moh.0b013e3283606162] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
PURPOSE OF REVIEW Fibroblast growth factor (FGF) signaling activates many bone marrow cell types, including various stem cells, osteoblasts, and osteoclasts. However, the role of FGF signaling in regulation of normal and leukemic stem cells is poorly understood. This review highlights the physiological roles of FGF signaling in regulating bone marrow mesenchymal and hematopoietic stem and progenitor cells (MSPCs and HSPCs) and their dynamic microenvironment. In addition, this review summarizes the recent studies which provide an overview of FGF-activated mechanisms regulating physiological stem cell maintenance, self-renewal, and motility. RECENT FINDINGS Current results indicate that partial deficiencies in FGF signaling lead to mild defects in hematopoiesis and bone remodeling. However, FGF signaling was shown to be crucial for stem cell self-renewal and for proper hematopoietic poststress recovery. FGF signaling activation was shown to be important also for rapid AMD3100 or post 5-fluorouracil-induced HSPC mobilization. In vivo, FGF-2 administration successfully expanded both MSPCs and HSPCs. FGF-induced expansion was characterized by enhanced HSPC cycling without further exhaustion of the stem cell pool. In addition, FGF signaling expands and remodels the supportive MSPC niche cells. Finally, FGF signaling is constitutively activated in many leukemias, suggesting that malignant HSPCs exploit this pathway for their constant expansion and for remodeling a malignant-supportive microenvironment. SUMMARY The summarized studies, concerning regulation of stem cells and their microenvironment, suggest that FGF signaling manipulation can serve to improve current clinical stem cell mobilization and transplantation protocols. In addition, it may help to develop therapies specifically targeting leukemic stem cells and their supportive microenvironment.
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Su N, Chen M, Chen S, Li C, Xie Y, Zhu Y, Zhang Y, Zhao L, He Q, Du X, Chen D, Chen L. Overexpression of H1 calponin in osteoblast lineage cells leads to a decrease in bone mass by disrupting osteoblast function and promoting osteoclast formation. J Bone Miner Res 2013; 28:660-71. [PMID: 23044709 PMCID: PMC3716280 DOI: 10.1002/jbmr.1778] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/20/2012] [Revised: 08/24/2012] [Accepted: 09/07/2012] [Indexed: 02/03/2023]
Abstract
H1 calponin (CNN1) is known as a smooth muscle-specific, actin-binding protein which regulates smooth muscle contractive activity. Although previous studies have shown that CNN1 has effect on bone, the mechanism is not well defined. To investigate the role of CNN1 in maintaining bone homeostasis, we generated transgenic mice overexpressing Cnn1 under the control of the osteoblast-specific 3.6-kb Col1a1 promoter. Col1a1-Cnn1 transgenic mice showed delayed bone formation at embryonic stage and decreased bone mass at adult stage. Morphology analyses showed reduced trabecular number, thickness and defects in bone formation. The proliferation and migration of osteoblasts were decreased in Col1a1-Cnn1 mice due to alterations in cytoskeleton. The early osteoblast differentiation of Col1a1-Cnn1 mice was increased, but the late stage differentiation and mineralization of osteoblasts derived from Col1a1-Cnn1 mice were significantly decreased. In addition to impaired bone formation, the decreased bone mass was also associated with enhanced osteoclastogenesis. Tartrate-resistant acid phosphatase (TRAP) staining revealed increased osteoclast numbers in tibias of 2-month-old Col1a1-Cnn1 mice, and increased numbers of osteoclasts co-cultured with Col1a1-Cnn1 osteoblasts. The ratio of RANKL to OPG was significantly increased in Col1a1-Cnn1 osteoblasts. These findings reveal a novel function of CNN1 in maintaining bone homeostasis by coupling bone formation to bone resorption.
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Affiliation(s)
- Nan Su
- Center of Bone Metabolism and Repair, State Key Laboratory of Trauma, Burns and Combined Injury, Trauma Center, Institute of Surgery Research, Daping Hospital, Third Military Medical University, Chongqing, China
| | - Maomao Chen
- Center of Bone Metabolism and Repair, State Key Laboratory of Trauma, Burns and Combined Injury, Trauma Center, Institute of Surgery Research, Daping Hospital, Third Military Medical University, Chongqing, China
| | - Siyu Chen
- Center of Bone Metabolism and Repair, State Key Laboratory of Trauma, Burns and Combined Injury, Trauma Center, Institute of Surgery Research, Daping Hospital, Third Military Medical University, Chongqing, China
| | - Can Li
- Center of Bone Metabolism and Repair, State Key Laboratory of Trauma, Burns and Combined Injury, Trauma Center, Institute of Surgery Research, Daping Hospital, Third Military Medical University, Chongqing, China
| | - Yangli Xie
- Center of Bone Metabolism and Repair, State Key Laboratory of Trauma, Burns and Combined Injury, Trauma Center, Institute of Surgery Research, Daping Hospital, Third Military Medical University, Chongqing, China
| | - Ying Zhu
- Center of Bone Metabolism and Repair, State Key Laboratory of Trauma, Burns and Combined Injury, Trauma Center, Institute of Surgery Research, Daping Hospital, Third Military Medical University, Chongqing, China
| | - Yaozong Zhang
- Center of Bone Metabolism and Repair, State Key Laboratory of Trauma, Burns and Combined Injury, Trauma Center, Institute of Surgery Research, Daping Hospital, Third Military Medical University, Chongqing, China
| | - Ling Zhao
- Center of Bone Metabolism and Repair, State Key Laboratory of Trauma, Burns and Combined Injury, Trauma Center, Institute of Surgery Research, Daping Hospital, Third Military Medical University, Chongqing, China
| | - Qifen He
- Center of Bone Metabolism and Repair, State Key Laboratory of Trauma, Burns and Combined Injury, Trauma Center, Institute of Surgery Research, Daping Hospital, Third Military Medical University, Chongqing, China
| | - Xiaolan Du
- Center of Bone Metabolism and Repair, State Key Laboratory of Trauma, Burns and Combined Injury, Trauma Center, Institute of Surgery Research, Daping Hospital, Third Military Medical University, Chongqing, China
| | - Di Chen
- Department of Biochemistry, Rush University Medical Center, Chicago, IL, USA
| | - Lin Chen
- Center of Bone Metabolism and Repair, State Key Laboratory of Trauma, Burns and Combined Injury, Trauma Center, Institute of Surgery Research, Daping Hospital, Third Military Medical University, Chongqing, China
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25
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Agas D, Marchetti L, Hurley MM, Sabbieti MG. Prostaglandin F2α: a bone remodeling mediator. J Cell Physiol 2012; 228:25-9. [PMID: 22585670 DOI: 10.1002/jcp.24117] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Prostaglandin F2α (PGF2α) plays multiple roles on bone metabolism by regulating a wide range of signaling pathways. PGF2α, via activation of PKC, stimulates Na-dependent inorganic phosphate (Pi) transport system in osteoblasts; up-regulates interleukin (IL)-6 synthesis; increases vascular endothelial growth factor (VEGF). In addition, PGF2α acts as a strong mitogenic and survival agent on osteoblasts, and these effects are, at least in part, mediated by the binding of fibroblast growth factor-2 (FGF-2) to the specific receptor FGFR1. The understanding of PGF2α intracellular network, albeit complex to clarify, provides molecular bases useful to identify the players of osteoblast proliferation, apoptosis, and the associated angiogenic processes. Indeed, the molecular mechanism that underline PGF2α-regulated bone metabolism may be a promising platform for the development of novel targeted therapies in the treatment of bone disorders and disease.
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Affiliation(s)
- Dimitrios Agas
- School of Biosciences and Biotechnology, University of Camerino, Camerino (MC), Italy
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26
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Fei Y, Hurley MM. Role of fibroblast growth factor 2 and Wnt signaling in anabolic effects of parathyroid hormone on bone formation. J Cell Physiol 2012; 227:3539-45. [PMID: 22378151 DOI: 10.1002/jcp.24075] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Osteoporosis poses enormous health and economic burden worldwide. One of the very few anabolic agents for osteoporosis is parathyroid hormone (PTH). Although great progress has been made since the FDA approved PTH in 2002, the detailed mechanisms of the bone anabolic effects of intermittent PTH treatment is still not well understood. PTH bone anabolic effect is regulated by extracellular factors. Maximal bone anabolic effect of PTH requires fibroblast growth factor 2 (FGF2) signaling, which might be mediated by transcription factor activating transcription factor 4 (ATF4). Maximal bone anabolic effect of PTH also requires Wnt signaling. Particularly, Wnt antagonists such as sclerostin, dickkopf 1 (DKK1) and secreted frizzled related protein 1 (sFRP1) are promising targets to increase bone formation. Interestingly, FGF2 signaling modulates Wnt/β-Catenin signaling pathway in bone. Therefore, multiple signaling pathways utilized by PTH are cross talking and working together to promote bone formation. Extensive studies on the mechanisms of action of PTH will help to identify new pathways that regulate bone formation, to improve available agents to stimulate bone formation, and to identify potential new anabolic agents for osteoporosis.
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Affiliation(s)
- Yurong Fei
- Department of Medicine, University of Connecticut Health Center, Farmington, CT 06030, USA
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27
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FGF-2 expands murine hematopoietic stem and progenitor cells via proliferation of stromal cells, c-Kit activation, and CXCL12 down-regulation. Blood 2012; 120:1843-55. [DOI: 10.1182/blood-2011-11-394692] [Citation(s) in RCA: 83] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Abstract
Cytokine-induced expansion of hematopoietic stem and progenitor cells (HSPCs) is not fully understood. In the present study, we show that whereas steady-state hematopoiesis is normal in basic fibroblast growth factor (FGF-2)–knockout mice, parathyroid hormone stimulation and myeloablative treatments failed to induce normal HSPC proliferation and recovery. In vivo FGF-2 treatment expanded stromal cells, including perivascular Nestin+ supportive stromal cells, which may facilitate HSPC expansion by increasing SCF and reducing CXCL12 via mir-31 up-regulation. FGF-2 predominantly expanded a heterogeneous population of undifferentiated HSPCs, preserving and increasing durable short- and long-term repopulation potential. Mechanistically, these effects were mediated by c-Kit receptor activation, STAT5 phosphorylation, and reduction of reactive oxygen species levels. Mice harboring defective c-Kit signaling exhibited abrogated HSPC expansion in response to FGF-2 treatment, which was accompanied by elevated reactive oxygen species levels. The results of the present study reveal a novel mechanism underlying FGF-2–mediated in vivo expansion of both HSPCs and their supportive stromal cells, which may be used to improve stem cell engraftment after clinical transplantation.
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28
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Du X, Xie Y, Xian CJ, Chen L. Role of FGFs/FGFRs in skeletal development and bone regeneration. J Cell Physiol 2012; 227:3731-43. [DOI: 10.1002/jcp.24083] [Citation(s) in RCA: 117] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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29
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Abstract
Fibroblast growth factors (FGFs) are important molecules that control bone formation. FGF act by activating FGF receptors (FGFRs) and downstream signaling pathways that control cells of the osteoblast lineage. Recent advances have been made in the identification of FGF/FGFR signaling pathways that control osteogenesis. Indeed, studies of mouse and human models provided novel insights into the signaling pathways that control bone formation. Genomic studies also highlighted the implication of molecular targets of FGF/FGFR signaling regulating osteoblastogenesis. Recent studies further revealed the important role of crosstalks between FGF/FGFR signaling and other signaling pathways in the regulation of osteogenesis. Finally, the importance of the mechanisms modulating FGFR degradation in the control of osteoblast differentiation has been recently revealed. This short review summarizes the recently described mechanisms underlying FGF/FGFR signaling that are involved in the control of osteoblastogenesis. This knowledge may have potential therapeutic implications in skeletal disorders characterized by abnormal bone formation.
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Affiliation(s)
- Pierre J Marie
- Laboratory of Osteoblast Biology and Pathology, INSERM UMR-606 and University Paris Diderot, Paris F-75475, France.
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30
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Walker EC, Poulton IJ, McGregor NE, Ho PWM, Allan EH, Quach JM, Martin TJ, Sims NA. Sustained RANKL response to parathyroid hormone in oncostatin M receptor-deficient osteoblasts converts anabolic treatment to a catabolic effect in vivo. J Bone Miner Res 2012; 27:902-12. [PMID: 22190112 DOI: 10.1002/jbmr.1506] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Parathyroid hormone (PTH) is the only approved anabolic agent for osteoporosis treatment. It acts via osteoblasts to stimulate both osteoclast formation and bone formation, with the balance between these two activities determined by the mode of administration. Oncostatin M (OSM), a gp130-dependent cytokine expressed by osteoblast lineage cells, has similar effects and similar gene targets in the osteoblast lineage. In this study, we investigated whether OSM might participate in anabolic effects of PTH. Microarray analysis and quantitative real-time polymerase chain reaction (qPCR) of PTH-treated murine stromal cells and primary calvarial osteoblasts identified significant regulation of gp130 and gp130-dependent coreceptors and ligands, including a significant increase in OSM receptor (OSMR) expression. To determine whether OSMR signaling is required for PTH anabolic action, 6-week-old male Osmr(-/-) mice and wild-type (WT) littermates were treated with hPTH(1-34) for 3 weeks. In WT mice, PTH increased trabecular bone volume and trabecular thickness. In contrast, the same treatment had a catabolic effect in Osmr(-/-) mice, reducing both trabecular bone volume and trabecular number. This was not explained by any alteration in the increased osteoblast formation and mineral apposition rate in response to PTH in Osmr(-/-) compared with WT mice. Rather, PTH treatment doubled osteoclast surface in Osmr(-/-) mice, an effect not observed in WT mice. Consistent with this finding, when osteoclast precursors were cultured in the presence of osteoblasts, more osteoclasts were formed in response to PTH when Osmr(-/-) osteoblasts were used. Neither PTH1R mRNA levels nor cAMP response to PTH were modified in Osmr(-/-) osteoblasts. However, RANKL induction in PTH-treated Osmr(-/-) osteoblasts was sustained at least until 24 hours after PTH exposure, an effect not observed in WT osteoblasts. These data indicate that the transient RANKL induction by intermittent PTH administration, which is associated with its anabolic action, is changed to a prolonged induction in OSMR-deficient osteoblasts, resulting in bone destruction.
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Affiliation(s)
- Emma C Walker
- St. Vincent's Institute of Medical Research, Melbourne, Victoria, Australia
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31
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Marie PJ. Fibroblast growth factor signaling controlling bone formation: An update. Gene 2012; 498:1-4. [DOI: 10.1016/j.gene.2012.01.086] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2011] [Revised: 01/23/2012] [Accepted: 01/29/2012] [Indexed: 10/14/2022]
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32
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Novince CM, Michalski MN, Koh AJ, Sinder BP, Entezami P, Eber MR, Pettway GJ, Rosol TJ, Wronski TJ, Kozloff KM, McCauley LK. Proteoglycan 4: a dynamic regulator of skeletogenesis and parathyroid hormone skeletal anabolism. J Bone Miner Res 2012; 27:11-25. [PMID: 21932346 PMCID: PMC4118835 DOI: 10.1002/jbmr.508] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/27/2011] [Revised: 08/08/2011] [Accepted: 08/25/2011] [Indexed: 12/16/2022]
Abstract
Proteoglycan 4 (Prg4), known for its lubricating and protective actions in joints, is a strong candidate regulator of skeletal homeostasis and parathyroid hormone (PTH) anabolism. Prg4 is a PTH-responsive gene in bone and liver. Prg4 null mutant mice were used to investigate the impact of proteoglycan 4 on skeletal development, remodeling, and PTH anabolic actions. Young Prg4 mutant and wild-type mice were administered intermittent PTH(1-34) or vehicle daily from 4 to 21 days. Young Prg4 mutant mice had decreased growth plate hypertrophic zones, trabecular bone, and serum bone formation markers versus wild-type mice, but responded with a similar anabolic response to PTH. Adult Prg4 mutant and wild-type mice were administered intermittent PTH(1-34) or vehicle daily from 16 to 22 weeks. Adult Prg4 mutant mice had decreased trabecular and cortical bone, and blunted PTH-mediated increases in bone mass. Joint range of motion and animal mobility were lower in adult Prg4 mutant versus wild-type mice. Adult Prg4 mutant mice had decreased marrow and liver fibroblast growth factor 2 (FGF-2) mRNA and reduced serum FGF-2, which were normalized by PTH. A single dose of PTH decreased the PTH/PTHrP receptor (PPR), and increased Prg4 and FGF-2 to a similar extent in liver and bone. Proteoglycan 4 supports endochondral bone formation and the attainment of peak trabecular bone mass, and appears to support skeletal homeostasis indirectly by protecting joint function. Bone- and liver-derived FGF-2 likely regulate proteoglycan 4 actions supporting trabeculae formation. Blunted PTH anabolic responses in adult Prg4 mutant mice are associated with altered biomechanical impact secondary to joint failure.
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Affiliation(s)
- Chad M Novince
- Department of Periodontics and Oral Medicine, School of Dentistry, University of Michigan, Ann Arbor, MI, USA
| | - Megan N Michalski
- Department of Periodontics and Oral Medicine, School of Dentistry, University of Michigan, Ann Arbor, MI, USA
| | - Amy J Koh
- Department of Periodontics and Oral Medicine, School of Dentistry, University of Michigan, Ann Arbor, MI, USA
| | - Benjamin P Sinder
- Department of Orthopaedic Surgery, Medical School, University of Michigan, Ann Arbor, MI, USA
| | - Payam Entezami
- Department of Periodontics and Oral Medicine, School of Dentistry, University of Michigan, Ann Arbor, MI, USA
| | - Matthew R Eber
- Department of Periodontics and Oral Medicine, School of Dentistry, University of Michigan, Ann Arbor, MI, USA
| | - Glenda J Pettway
- Department of Periodontics and Oral Medicine, School of Dentistry, University of Michigan, Ann Arbor, MI, USA
| | - Thomas J Rosol
- Department of Veterinary Biosciences, College of Veterinary Medicine, The Ohio State University, Columbus, OH, USA
| | - Thomas J Wronski
- Department of Physiological Sciences, University of Florida, Gainesville, FL, USA
| | - Ken M Kozloff
- Department of Orthopaedic Surgery, Medical School, University of Michigan, Ann Arbor, MI, USA
| | - Laurie K McCauley
- Department of Periodontics and Oral Medicine, School of Dentistry, University of Michigan, Ann Arbor, MI, USA
- Department of Pathology, Medical School, University of Michigan, Ann Arbor, MI, USA
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33
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Koh AJ, Novince CM, Li X, Wang T, Taichman RS, McCauley LK. An irradiation-altered bone marrow microenvironment impacts anabolic actions of PTH. Endocrinology 2011; 152:4525-36. [PMID: 22045660 PMCID: PMC3230047 DOI: 10.1210/en.2011-1515] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
PTH stimulates bone formation and increases hematopoietic stem cells through mechanisms as yet uncertain. The purpose of this study was to identify mechanisms by which PTH links actions on cells of hematopoietic origin with osteoblast-mediated bone formation. C57B6 mice (10 d) were nonlethally irradiated and then administered PTH for 5-20 d. Irradiation reduced bone marrow cellularity with retention of cells lining trabeculae. PTH anabolic activity was greater in irradiated vs. nonirradiated mice, which could not be accounted for by altered osteoblasts directly or osteoclasts but instead via an altered bone marrow microenvironment. Irradiation increased fibroblast growth factor 2, TGFβ, and IL-6 mRNA levels in the bone marrow in vivo. Irradiation decreased B220 cell numbers, whereas the percent of Lin(-)Sca-1(+)c-kit(+) (LSK), CD11b(+), CD68(+), CD41(+), Lin(-)CD29(+)Sca-1(+) cells, and proliferating CD45(-)Nestin(+) cells was increased. Megakaryocyte numbers were reduced with irradiation and located more closely to trabecular surfaces with irradiation and PTH. Bone marrow TGFβ was increased in irradiated PTH-treated mice, and inhibition of TGFβ blocked the PTH augmentation of bone in irradiated mice. In conclusion, irradiation created a permissive environment for anabolic actions of PTH that was TGFβ dependent but osteoclast independent and suggests that a nonosteoclast source of TGFβ drives mesenchymal stem cell recruitment to support PTH anabolic actions.
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Affiliation(s)
- A J Koh
- Department of Periodontics, University of Michigan, Ann Arbor, Michigan 48109-1078, USA
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34
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Datsis GA, Berdiaki A, Nikitovic D, Mytilineou M, Katonis P, Karamanos NK, Tzanakakis GN. Parathyroid hormone affects the fibroblast growth factor-proteoglycan signaling axis to regulate osteosarcoma cell migration. FEBS J 2011; 278:3782-92. [DOI: 10.1111/j.1742-4658.2011.08300.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
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35
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Yuan Q, Sato T, Densmore M, Saito H, Schüler C, Erben RG, Lanske B. FGF-23/Klotho signaling is not essential for the phosphaturic and anabolic functions of PTH. J Bone Miner Res 2011; 26:2026-35. [PMID: 21590742 PMCID: PMC4343543 DOI: 10.1002/jbmr.433] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Parathyroid hormone (PTH) is widely recognized as a key regulator of mineral ion homeostasis. Daily intermittent administration of PTH is the only currently available anabolic therapy for bone disorders such as osteoporosis. Recent studies have shown that PTH increases transcription and secretion of fibroblast growth factor 23 (FGF-23), another important regulator of phosphate homeostasis and skeletal metabolism. However, the full relationship between PTH and FGF-23 is largely unknown. This study evaluated the effect of FGF-23/Klotho signaling on the phosphaturic and anabolic functions of PTH. Eight-day-old wild-type (WT) Fgf23(-/-) and Kl(-/-) mice were injected with 100 µg/kg PTH(1-34) or vehicle daily for a 2-week-period and then euthanized. Intermittent injection of PTH successfully reduced the serum phosphate levels and reversed the hyperphosphatemia of Fgf23(-/-) and Kl(-/-) mice. Bone changes were analyzed in the distal femur metaphysis by peripheral quantitative computed tomography (pQCT), micro-computed tomography (µCT), and histomorphometry. PTH treatment induced substantial increases in bone mineral density (BMD) and trabecular bone volume in each mouse genotype. Expression of osteoblastic marker genes, including Runx2, Col1, Alp, Ocn, and Sost, was similarly altered. In addition, primary osteoblasts were isolated and treated with 100 nM PTH in vitro. PTH treatment similarly induced cAMP accumulation and phosphorylation of ERK1/2 and CREB in the osteoblasts from each genotype. Taken together, our results demonstrate that FGF-23/Klotho signaling is not essential for the phosphaturic and anabolic functions of PTH, suggesting that PTH can function as a therapeutic agent to improve the skeletal quality of patients even in the presence of abnormal serum FGF-23 levels.
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Affiliation(s)
- Quan Yuan
- Department of Developmental Biology, Harvard School of Dental Medicine, Boston, MA 02115, USA
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36
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Bashutski JD, Wang HL. Biologic Agents to Promote Periodontal Regeneration and Bone Augmentation. Clin Adv Periodontics 2011; 1:80-87. [DOI: 10.1902/cap.2011.110044] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2011] [Accepted: 06/08/2011] [Indexed: 11/13/2022]
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37
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Fei Y, Xiao L, Hurley MM. The impaired bone anabolic effect of PTH in the absence of endogenous FGF2 is partially due to reduced ATF4 expression. Biochem Biophys Res Commun 2011; 412:160-4. [PMID: 21806973 DOI: 10.1016/j.bbrc.2011.07.066] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2011] [Accepted: 07/18/2011] [Indexed: 02/06/2023]
Abstract
Parathyroid hormone (PTH) is currently the only approved anabolic agent for osteoporosis pharmacotherapy in the USA. However, the molecular and cellular mechanisms underlying which intermittent PTH stimulates bone formation are not fully established. Activating transcription factor 4 (ATF4) was recently identified to be a downstream target of PTH signaling in osteoblasts and FGF2 is able to rapidly increase ATF4 mRNA and protein expression in osteoblasts. Furthermore, ATF4 expression is markedly reduced in Fgf2(-/-) osteoblasts. In addition, FGF2 is required for the anabolic action of PTH on bone formation. Therefore, we hypothesize that the impaired anabolic effect of PTH in Fgf2(-/-) mice is partially due to reduced ATF4 expression. To test this hypothesis, we examined the ability of PTH to increase ATF4 expression in vitro and in vivo. In vitro data showed that PTH induced a significant increase in ATF4 mRNA expression as early as 15 min in Fgf2(+/+) primary bone marrow stromal cells (BMSCs) but not in Fgf2(-/-) BMSCs. In vivo data showed that treatment with PTH (1-34) (40 μg/kg/d) treatment for 2 weeks in 21-23 months female mice increased lumbar vertebrae bone mineral density in Fgf2(+/+) (13.8% increase). In contrast there was a 2.1% decrease in Fgf2(-/-) mice. Interestingly, basal ATF4 mRNA expression in tibiae was significantly lower in Fgf2(-/-) mice (46% decrease) compared to Fgf2(+/+) mice. PTH treatment increased ATF4 mRNA by 97% (p<0.05) in Fgf2(+/+) compared to 8% (p=0.57) in Fgf2(-/-) mice. Immunohistochemistry of vertebrae showed less ATF4 staining in Fgf2(-/-) tissue, and treatment with PTH increased ATF4 staining in Fgf2(+/+) but the increase was attenuated in Fgf2(-/-) tissue. In summary, reduced ATF4 expression may result in decreased osteoblast differentiation, and possibly contribute to the impaired stimulation of PTH on bone formation in Fgf2(-/-) mice.
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Affiliation(s)
- Yurong Fei
- University of Connecticut Health Center, Farmington, CT 06030, USA.
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38
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Gupta RR, Yoo DJ, Hebert C, Niger C, Stains JP. Induction of an osteocyte-like phenotype by fibroblast growth factor-2. Biochem Biophys Res Commun 2010; 402:258-64. [PMID: 20934405 DOI: 10.1016/j.bbrc.2010.10.011] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2010] [Accepted: 10/04/2010] [Indexed: 01/24/2023]
Abstract
The purpose of this study was to characterize the molecular phenotype that occurs during the profound morphological shift of cultured osteogenic cells upon treatment with fibroblast growth factor-2 (FGF2). A time course of treatment with FGF2 was performed on an osteoblast cell line, primary bone marrow stromal cells and an osteocyte-like cell line. Morphologic changes were recorded, and gene profiling was carried out by real time PCR. By 8h of FGF2 treatment, there is a striking morphological shift of osteoblast and stromal cells to an elongated dendritic-like morphology that is remindful of osteocytes. In osteoblasts treated with FGF2, this morphologic shift is preceded by an induction of several osteocyte markers, including dentin matrix protein 1 (>20-fold) and E11 (>5-fold). There is a transient increase in the gene expression of sclerostin (3.5-fold) and PHEX (2.5-fold). Sclerostin regulation by FGF2 is complex, as gene expression becomes markedly inhibited by FGF2 at times points after 8h of treatment before rebounding at day 12. Analogous modulation of osteocyte markers is seen in bone marrow stromal cells and MLO-Y4 osteocyte-like cells. In conclusion, this study shows that FGF2 can regulate the transition of osteogenic cells towards the osteocyte lineage, as well as, regulate the expression of critical genes in osteocytes.
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Affiliation(s)
- Rishi R Gupta
- Department of Orthopaedics, University of Maryland, School of Medicine, Baltimore, MD 21201, USA
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39
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Pacifici R. The immune system and bone. Arch Biochem Biophys 2010; 503:41-53. [PMID: 20599675 DOI: 10.1016/j.abb.2010.05.027] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2010] [Revised: 05/26/2010] [Accepted: 05/27/2010] [Indexed: 02/06/2023]
Abstract
T cells and B cells produce large amounts of cytokines which regulate bone resorption and bone formation. These factors play a critical role in the regulation of bone turnover in health and disease. In addition, immune cells of the bone marrow regulate bone homeostasis by cross-talking with bone marrow stromal cells and osteoblastic cells via cell surface molecules. These regulatory mechanisms are particularly relevant for postmenopausal osteoporosis and hyperparathyroidism, two common forms of bone loss caused primarily by an expansion of the osteoclastic pool only partially compensated by a stimulation of bone formation. This article describes the cytokines and immune factors that regulate bone cells, the immune cells relevant to bone, examines the connection between T cells and bone in health and disease, and reviews the evidence in favor of a link between T cells and the mechanism of action of estrogen and PTH in bone.
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40
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Sierra OL, Towler DA. Runx2 trans-activation mediated by the MSX2-interacting nuclear target requires homeodomain interacting protein kinase-3. Mol Endocrinol 2010; 24:1478-97. [PMID: 20484411 DOI: 10.1210/me.2010-0029] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Runt-related transcription factor 2 (Runx2) and muscle segment homeobox homolog 2-interacting nuclear target (MINT) (Spen homolog) are transcriptional regulators critical for mammalian development. MINT enhances Runx2 activation of osteocalcin (OC) fibroblast growth factor (FGF) response element in an FGF2-dependent fashion in C3H10T1/2 cells. Although the MINT N-terminal RNA recognition motif domain contributes, the muscle segment homeobox homolog 2-interacting domain is sufficient for Runx2 activation. Intriguingly, Runx1 cannot replace Runx2 in this assay. To better understand this Runx2 signaling cascade, we performed structure-function analysis of the Runx2-MINT trans-activation relationship. Systematic truncation and domain swapping in Runx1:Runx2 chimeras identified that the unique Runx2 activation domain 3 (AD3), encompassed by residues 316-421, conveys MINT+FGF2 trans-activation in transfection assays. Ala mutagenesis of Runx2 Ser/Thr residues identified that S301 and T326 in AD3 are necessary for full MINT+FGF2 trans-activation. Conversely, phosphomimetic Asp substitution of these AD3 Ser/Thr residues enhanced activation by MINT. Adjacent Pro residues implicated regulation by a proline-directed protein kinase (PDPK). Systematic screening with PDPK inhibitors identified that the casein kinase-2/homeodomain-interacting protein kinase (HIPK)/dual specificity tyrosine phosphorylation regulated kinase inhibitor 2-dimethylamino-4,5,6,7-tetrabromo-1H-benzimidazole (DMAT), but not ERK, c-Jun N-terminal kinase, p38MAPK, or other casein kinase-2 inhibitors, abrogated Runx2-, MINT-, and FGF2-activation. Systematic small interfering RNA-mediated silencing of DMAT-inhibited PDPKs revealed that HIPK3 depletion reduced MINT+FGF2-dependent activation of Runx2. HIPK3 and Runx2 coprecipitate after in vitro transcription-translation, and recombinant HIPK3 recognizes Runx2 AD3 as kinase substrate. Furthermore, DMAT treatment and HIPK3 RNAi inhibited MINT+FGF2 activation of Runx2 AD3, and nuclear HIPK3 colocalized with MINT. HIPK3 antisense oligodeoxynucleotide selectively reduced Runx2 protein accumulation and OC gene expression in C3H10T1/2 cells. Thus, HIPK3 participates in MINT+FGF2 regulation of Runx2 AD3 activity and controls Runx2-dependent OC expression.
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Affiliation(s)
- Oscar L Sierra
- Washington University School of Medicine, Internal Medicine-Endocrinology/Metabolism, Campus Box 8301, 660 South Euclid Avenue, St. Louis, Missouri 63110, USA.
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Finkelstein JS, Wyland JJ, Lee H, Neer RM. Effects of teriparatide, alendronate, or both in women with postmenopausal osteoporosis. J Clin Endocrinol Metab 2010; 95:1838-45. [PMID: 20164296 PMCID: PMC2853981 DOI: 10.1210/jc.2009-1703] [Citation(s) in RCA: 184] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
CONTEXT Teriparatide increases both bone formation and bone resorption. OBJECTIVE We sought to determine whether combining teriparatide with an antiresorptive agent would alter its anabolic action. DESIGN AND SETTING This was a randomized controlled trial conducted in a single university hospital. PATIENTS AND INTERVENTION We randomized 93 postmenopausal women with low bone mineral density (BMD) to alendronate 10 mg daily (group 1), teriparatide 40 microg sc daily (group 2), or both (group 3) for 30 months. Teriparatide was begun at month 6. MAIN OUTCOME MEASURES BMD of the lumbar spine, proximal femur, proximal radius, and total body was measured by dual-energy x-ray absorptiometry (DXA) every 6 months. Lumbar spine trabecular BMD was measured at baseline and month 30 by quantitative computed tomography. Serum osteocalcin, N-terminal propeptide of type 1 collagen, and N-telopeptide levels were assessed frequently. Women who had at least one repeat DXA scan on therapy were included in the analyses (n = 69). RESULTS DXA spine BMD increased more in women treated with teriparatide alone than with alendronate alone (18 +/- 11 vs. 7 +/- 4%; P < 0.001) or both (18+/-11 vs. 12 +/- 9%; P = 0.045). Similarly, femoral neck BMD increased more in women treated with teriparatide alone than with alendronate alone (11 +/- 5 vs. 4 +/- 4%; P < 0.001) or both (11 +/- 5 vs. 3 +/- 5%; P < 0.001). Quantitative computed tomography spine BMD increased 1 +/- 7, 61 +/- 31, and 24 +/- 24% in groups 1, 2, and 3 (P < 0.001 for all comparisons). Serum osteocalcin, N-terminal propeptide of type 1 collagen, and cross-linked N-telopeptides of type I collagen increased more with teriparatide alone than with both (P < 0.001 for each marker). CONCLUSION Alendronate reduces the ability of teriparatide to increase BMD and bone turnover in women.
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Affiliation(s)
- Joel S Finkelstein
- Department of Medicine, Endocrine Unit, Massachusetts General Hospital, Boston, Massachusetts 02114, USA.
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Kramer I, Keller H, Leupin O, Kneissel M. Does osteocytic SOST suppression mediate PTH bone anabolism? Trends Endocrinol Metab 2010; 21:237-44. [PMID: 20074973 DOI: 10.1016/j.tem.2009.12.002] [Citation(s) in RCA: 95] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/13/2009] [Revised: 12/06/2009] [Accepted: 12/09/2009] [Indexed: 02/02/2023]
Abstract
Parathyroid hormone (PTH) has bone anabolic activity when administered intermittently, affecting cells of the osteoblastic lineage at various stages, yet much remains to be learned about precisely how PTH promotes osteoblastic bone formation. Recent discoveries revealed that PTH causes transcriptional suppression of the osteocyte marker gene SOST, which encodes the potent secreted bone formation inhibitor, sclerostin. This review addresses whether osteocytes, terminally differentiated cells of the osteoblastic lineage, which are entrapped within the mineralized bone matrix, contribute to PTH-induced bone formation responses via regulation of sclerostin levels, and discusses recent evidence on how the bone anabolic responses elicited by intermittent PTH treatment or by sclerostin inhibition overlap and diverge.
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Affiliation(s)
- Ina Kramer
- Musculoskeletal Disease Area, Novartis Institutes for BioMedical Research, CH-4002 Basel, Switzerland
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Affiliation(s)
- Natalie A Sims
- St. Vincent's Institute and Department of Medicine at St. Vincent's Hospital, The University of Melbourne, Fitzroy, Victoria, Australia
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Su N, Sun Q, Li C, Lu X, Qi H, Chen S, Yang J, Du X, Zhao L, He Q, Jin M, Shen Y, Chen D, Chen L. Gain-of-function mutation in FGFR3 in mice leads to decreased bone mass by affecting both osteoblastogenesis and osteoclastogenesis. Hum Mol Genet 2010; 19:1199-210. [PMID: 20053668 DOI: 10.1093/hmg/ddp590] [Citation(s) in RCA: 73] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Achondroplasia (ACH) is a short-limbed dwarfism resulting from gain-of-function mutations in fibroblast growth factor receptor 3 (FGFR3). Previous studies have shown that ACH patients have impaired chondrogenesis, but the effects of FGFR3 on bone formation and bone remodeling at adult stages of ACH have not been fully investigated. Using micro-computed tomography and histomorphometric analyses, we found that 2-month-old Fgfr3(G369C/+) mice (mouse model mimicking human ACH) showed decreased bone mass due to reduced trabecular bone volume and bone mineral density, defect in bone mineralization and increased osteoclast numbers and activity. Compared with primary cultures of bone marrow stromal cells (BMSCs) from wild-type mice, Fgfr3(G369C/+) cultures showed decreased cell proliferation, increased osteogenic differentiation including up-regulation of alkaline phosphatase activity and expressions of osteoblast marker genes, and reduced bone matrix mineralization. Furthermore, our studies also suggest that decreased cell proliferation and enhanced osteogenic differentiation observed in Fgfr3(G369C/+) BMSCs are caused by up-regulation of p38 phosphorylation and that enhanced Erk1/2 activity is responsible for the impaired bone matrix mineralization. In addition, in vitro osteoclast formation and bone resorption assays demonstrated that osteoclast numbers and bone resorption area were increased in cultured bone marrow cells derived from Fgfr3(G369C/+) mice. These findings demonstrate that gain-of-function mutation in FGFR3 leads to decreased bone mass by regulating both osteoblast and osteoclast activities. Our studies provide new insight into the mechanism underlying the development of ACH.
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Affiliation(s)
- Nan Su
- State Key Laboratory of Trauma, Burns and Combined Injury, Trauma Center, Institute of Surgery Research, Daping Hospital, Third Military Medical University, Chongqing, China
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Critical role of activating transcription factor 4 in the anabolic actions of parathyroid hormone in bone. PLoS One 2009; 4:e7583. [PMID: 19851510 PMCID: PMC2762317 DOI: 10.1371/journal.pone.0007583] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2009] [Accepted: 10/05/2009] [Indexed: 12/14/2022] Open
Abstract
Parathyroid hormone (PTH) is a potent anabolic agent for the treatment of osteoporosis. However, its mechanism of action in osteoblast and bone is not well understood. In this study, we show that the anabolic actions of PTH in bone are severely impaired in both growing and adult ovariectomized mice lacking bone-related activating transcription factor 4 (ATF4). Our study demonstrates that ATF4 deficiency suppresses PTH-stimulated osteoblast proliferation and survival and abolishes PTH-induced osteoblast differentiation, which, together, compromise the anabolic response. We further demonstrate that the PTH-dependent increase in osteoblast differentiation is correlated with ATF4-dependent up-regulation of Osterix. This regulation involves interactions of ATF4 with a specific enhancer sequence in the Osterix promoter. Furthermore, actions of PTH on Osterix require this same element and are associated with increased binding of ATF4 to chromatin. Taken together these experiments establish a fundamental role for ATF4 in the anabolic actions of PTH on the skeleton.
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Abstract
The striking clinical benefit of PTH in osteoporosis began a new era of skeletal anabolic agents. Several studies have been performed, new studies are emerging out and yet controversies remain on PTH anabolic action in bone. This review focuses on the molecular aspects of PTH and PTHrP signaling in light of old players and recent advances in understanding the control of osteoblast proliferation, differentiation and function.
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Affiliation(s)
- Nabanita S Datta
- Division Endocrinology, Department Internal Medicine, Wayne State University School of Medicine, 421 East Canfield Avenue, Detroit, Michigan 48201, USA.
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Azhar M, Yin M, Zhou M, Li H, Mustafa M, Nusayr E, Keenan JB, Chen H, Pawlosky S, Gard C, Grisham C, Sanford LP, Doetschman T. Gene targeted ablation of high molecular weight fibroblast growth factor-2. Dev Dyn 2009; 238:351-7. [PMID: 19105223 DOI: 10.1002/dvdy.21835] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Fibroblast growth factor-2 (FGF2) is produced as high molecular weight isoforms (HMW) and a low molecular weight isoform (LMW) by means of alternative usage of translation start sites in a single Fgf2 mRNA. Although the physiological function of FGF2 and FGF2 LMW has been investigated in myocardial capillarogenesis during normal cardiac growth, the role of FGF2 HMW has not been determined. Here, we report the generation of FGF2 HMW-deficient mice in which FGF2 HMW isoforms are ablated by the Tag-and-Exchange gene targeting technique. These mice are normal and fertile with normal fecundity, and have a normal life span. Histological, immunohistochemical, and morphometric analyses indicate normal myocardial architecture, blood vessel, and cardiac capillary density in young adult FGF2 HMW-deficient mice. These mice along with the FGF2- and FGF2 LMW-deficient mice that we have generated previously will be very useful for elucidating the differential functions of FGF2 isoforms in pathophysiology of cardiovascular diseases.
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Affiliation(s)
- Mohamad Azhar
- BIO5 Institute, and Department of Cell Biology and Anatomy, University of Arizona, Tucson, Arizona, USA
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Robling AG, Childress P, Yu J, Cotte J, Heller A, Philip BK, Bidwell JP. Nmp4/CIZ suppresses parathyroid hormone-induced increases in trabecular bone. J Cell Physiol 2009; 219:734-43. [PMID: 19189321 DOI: 10.1002/jcp.21717] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The nucleocytoplasmic shuttling transcription factor Nmp4/CIZ (nuclear matrix protein 4/cas interacting zinc finger protein) is a ubiquitously expressed protein that regulates both cytoplasmic and nuclear activities. In the nucleus, Nmp4/CIZ represses transcription of genes crucial to osteoblast differentiation and genes activated by various anabolic stimuli, including parathyroid hormone (PTH). We investigated the role of Nmp4/CIZ in the PTH-induced increase in bone by engineering mice with loss-of-function mutations in the Nmp4/CIZ gene, and treating 10-week-old female mice with anabolic doses of human PTH (1-34) at 30 microg/kg/day, 7 day/week, for 7 weeks or vehicle control. The untreated, baseline phenotype of the Nmp4-null mice between 8 and 16 weeks of age included a modest but significant increase in bone mineral density (BMD) and bone mineral content (BMC) compared to wild-type (WT) mice. Type I collagen mRNA expression was moderately elevated in the femurs of the Nmp4-null mice. The Nmp4 mutant alleles decreased body weight by 4% when expressed on a mixed background but the same alleles on a pure B6 background yielded a significant, 15% increase in body weight among the KO mice, compared to their WT controls. Hormone treatment equally enhanced BMD and BMC over vehicle-treated mice in both the WT and Nmp4-null groups but Nmp4-KO mice exhibited a significantly greater PTH-induced acquisition of femoral trabecular bone as compared to WT mice. These data support our hypothesis that Nmp4/CIZ is a transcriptional attenuator that suppresses osteoid synthesis and PTH-mediated acquisition of cancellous bone. J. Cell. Physiol. 219: 734-743, 2009. (c) 2009 Wiley-Liss, Inc.
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Affiliation(s)
- Alexander G Robling
- Department of Anatomy & Cell Biology, Indiana University School of Medicine (IUSM), Indianapolis, Indiana, USA
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Sabbieti MG, Agas D, Xiao L, Marchetti L, Coffin JD, Doetschman T, Hurley MM. Endogenous FGF-2 is critically important in PTH anabolic effects on bone. J Cell Physiol 2009; 219:143-51. [PMID: 19107841 DOI: 10.1002/jcp.21661] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Parathyroid hormone (PTH) increases fibroblast growth factor receptor-1 (FGFR1) and fibroblast growth factor-2 (FGF-2) expression in osteoblasts and the anabolic response to PTH is reduced in Fgf2-/- mice. This study examined whether candidate factors implicated in the anabolic response to PTH were modulated in Fgf2-/- osteoblasts. PTH increased Runx-2 protein expression in Fgf2+/+ but not Fgf2-/- osteoblasts. By immunocytochemistry, PTH treatment induced nuclear accumulation of Runx-2 only in Fgf2+/+ osteoblasts. PTH and FGF-2 regulate Runx-2 via activation of the cAMP response element binding proteins (CREBs). Western blot time course studies showed that PTH increased phospho-CREB within 15 min that was sustained for 24 h in Fgf2+/+ but had no effect in Fgf2-/- osteoblasts. Silencing of FGF-2 in Fgf2+/+ osteoblasts blocked the stimulatory effect of PTH on Runx-2 and CREBs phosphorylation. Studies of the effects of PTH on proteins involved in osteoblast precursor proliferation and apoptosis showed that PTH increased cyclinD1-cdk4/6 protein in Fgf2+/+ but not Fgf2-/- osteoblasts. Interestingly, PTH increased the cell cycle inhibitor p21/waf1 in Fgf2-/- osteoblasts. PTH increased Bcl-2/Bax protein ratio in Fgf2+/+ but not Fgf2-/- osteoblasts. In addition PTH increased cell viability in Fgf2+/+ but not Fgf2-/- osteoblasts. These data suggest that endogenous FGF-2 is important in PTH effects on osteoblast proliferation, differentiation, and apoptosis. Reduced expression of these factors may contribute to the reduced anabolic response to PTH in the Fgf2-/- mice. Our results strongly indicate that the anabolic PTH effect is dependent in part on FGF-2 expression.
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Affiliation(s)
- Maria Giovanna Sabbieti
- Department of Comparative Morphology and Biochemistry, University of Camerino, Camerino (MC), Italy
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Sabbieti MG, Agas D, Materazzi S, Capacchietti M, Materazzi G, Hurley MM, Menghi G, Marchetti L. Prostaglandin F2alpha involves heparan sulphate sugar chains and FGFRs to modulate osteoblast growth and differentiation. J Cell Physiol 2008; 217:48-59. [PMID: 18459126 DOI: 10.1002/jcp.21471] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The present investigation extends our previous studies on PGF2alpha-mediated signalling in osteoblast metabolism. In particular, the role of PGF2alpha as modulator of heparan sulphate proteoglycans (HSPGs), fibroblast growth factor 2 (FGF-2) and fibroblast growth factor receptors (FGFRs) was evaluated. We hereby reported the novel observation that PGF2alpha was able to promote the formation of HSPGs/FGF-2/FGFRs complexes. Moreover, our data suggested that PGF2alpha could induce new synthesis of heparan sulphate (HS) chains on osteoblasts by a mechanism involving a modulation of MAPK signalling and that HS is required for the regulation of FGF-2 induced by PGF2alpha. Indeed, a proteolytic cleavage of HSPGs with heparinase III (Hep III) prior to PGF2alpha administration down-regulated the basal expression of phospho-p44/42, likely inhibiting FGFRs tyrosine kinase activity. Interestingly, MAPK signalling influenced syntheses and subcellular localization of FGF-2, its specific receptor and HS. In addition, the proteolytic cleavage by Hep III and the MAPK kinase inhibition by PD-98059 also revealed that PGF2alpha induced cell proliferation is dependent on HSPGs and FGF-2 specific receptor, respectively. Of further relevance of this study, we demonstrated, by using a specific siRNA for FGFR1, that PGF2alpha modulates Runx2 expression by FGFR1 and HS.
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Affiliation(s)
- Maria Giovanna Sabbieti
- Department of Comparative Morphology and Biochemistry, University of Camerino, Camerino (MC), Italy
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